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.\" Troff code generated by TPS Convert from ITU Original Files
.\"                 Not Copyright ( c) 1991 
.\"
.\" Assumes tbl, eqn, MS macros, and lots of luck.
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.EN
.nr LL 40.5P
.nr ll 40.5P
.nr HM 3P
.nr FM 6P
.nr PO 4P
.nr PD 9p
.po 4P

.rs
\v | 5i'
.sp 1P
.ce 1000
\v'3P'
SECTION\ 7
.ce 0
.sp 1P
.ce 1000
\fBTIME\ DIVISION\ MULTIPLEXING\fR 
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ R.100\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBTRANSMISSION\ CHARACTERISTICS\ OF\ INTERNATIONAL\ TDM\ LINKS\fR 
.EF '%	Fascicle\ VII.1\ \(em\ Rec.\ R.100''
.OF '''Fascicle\ VII.1\ \(em\ Rec.\ R.100	%'
.ce 0
.sp 1P
.ce 1000
\fI(Geneva, 1980, modified at Melbourne, 1988)\fR 
.sp 9p
.RT
.ce 0
.sp 1P
.PP
\fINote\fR \ \(em\ The application of TDM systems
providing code\(hy and speed\(hyindependent channels in addition to code\(hy 
and 
speed\(hydependent channels is a subject for further study.
.sp 1P
.RT
.sp 2P
.LP
\fB1\fR 	\fBAnalogue path links\fR 
.sp 1P
.RT
.PP
1.1
Standard telephone carrier systems with 4\(hykHz and 3\(hykHz spaced channels 
permit homogeneous time division multiplex (TDM) telegraph systems, operated 
in association with 2400\(hybit/s data modems, to provide the capacities 
of telegraph channels shown in Table\ 1/R.100. 
.sp 9p
.RT
.ce
\fBH.T. [T1.100]\fR 
.ce
TABLE\ 1/R.100
.ce
\fBChannel capacities of homogeneous TMD systems\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(48p) | cw(30p) sw(30p) sw(30p) sw(30p) sw(30p) sw(30p) , ^  | c | c | c | c | c | c.
TDM system type  (see Note 1)	 {
Quantity of channels provided by homogeneous system
 }
	50 baud	75 baud	100 baud	150 baud	200 baud	300 baud
_
.T&
lw(48p) | lw(30p) | lw(30p) | lw(30p) | lw(30p) | lw(30p) | lw(30p) .
\fIRecommandation\fR						
.T&
lw(48p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) .
R.101, Alternative A	46	22	\(em	\(em	\(em	\(em
.T&
lw(48p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) .
R.101, Alternative B	46	30	22	15	10	7
.T&
lw(48p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) | cw(30p) .
R.111	\ 8	(see Note 2)	\ 4	(see Note 2)	\ 2	2
.TE
.LP
\fINote\ 1\fR
\ \(em\ TDM systems complying with Recommendation R.101 provide
code\(hyand speed\(hydependent channels involving inherent regeneration of output
signals. The provision of channels above 75 bauds for Recommendation R.101,
Alternative A systems, is the subject of further study.
.LP
TDM systems complying with Recommendation R.111 provide code\(hyand
speed\(hyindependent channels by a transition coding process that does not include regeneration of the output signals. Furthermore. these systems may
have aggregate signalling rates of either 2.4, 4.8, 9.6 or 64 kbit/s.
.LP
\fINote\ 2\fR
\ \(em\ The Recommendation R.111 homogeneous system configurations shown
involve an aggregate rate of 2400 bit/s and 5% maximum isochronous distortion per channel due to sampling. 75\(hyand 150\(hybaud signals may be carried on nominal 100\(hyand 200\(hybaud channels respectively with proportionally less distortion.
.nr PS 9
.RT
.ad r
\fBTABLE 1/R.100 [T1.100], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
1.2
A 4\(hywire link is required in association with the data modem
employed to provide satisfactory transmission for the 2400\(hybit/s duplex
aggregate signals of an international TDM system.
.PP
1.3
The data modem employed should preferably comply with the
appropriate aspects of the Series\ V Recommendations. Multiple 2400\(hybit/s
aggregates may be multiplexed onto the same 4\(hywire link using the appropriate 
internal multiplexing facilities of a Recommendation\ V.29\ [1] modem. 
The 
reliability and availability of derived telegraph channels will, however, be
highly dependent on the stability and characteristics of the bearer, modem 
and system arrangements adopted. 
.PP
1.4
The conditions of use of international TDM links are generally
similar to those for VFT links, described in Recommendation\ H.22\ [2]. The
requirements of the actual V\(hySeries modem employed however, should be
additionally respected.
.PP
\fINote\fR \ \(em\ This subject is under study in Joint Working Party LTG, 
Study Group\ IV and Study Group\ IX. 
.PP
1.5
PCM (pulse code modulation) telephone channels complying with
Recommendation\ G.712\ [3] are also generally suitable as bearers for TDM
telegraph systems associated with modems complying with the Series\ V
Recommendations. However, possible transmission arrangements involving 
tandem connection of a number of PCM channels require further study. 
.PP
1.6
Recommendation R.111, in \(sc\ 1.2.1, provides
for the use of modems complying with the Recommendation cited in\ [4].
.sp 2P
.LP
\fB2\fR 	\fBDigital path links\fR 
.sp 1P
.RT
.PP
2.1
64 kbit/s international digital transmission circuits are realized by PCM 
time slots or via TDMA satellite systems. SCPC (single channel per 
carrier) satellite systems provide 56\ kbit/s channels. Primary groups
(60\(hy108\ kHz) in conjunction with V.36\ [4] modems may also be used.
.sp 9p
.RT
.sp 2P
.LP
2.2
	\fI64 kbit/s TDM link\fR 
.sp 1P
.RT
.PP
2.2.1 
Recommendation R.111, \(sc\ 1 defines the telegraph TDM systems at
64\ kbit/s.
.sp 9p
.RT
.PP
2.2.2
Recommendations X.50 [5] and X.51 [6] set out the parameters of
envelope interleaving TDM systems at 64\ kbit/s, which provide\ 0.6, 2.4, 4.8
and 9.6\ kbit/s tributary data channels. These data channels can be used to
transfer the aggregate signals of TDM systems at 0.6\ kbit/s
(Recommendation\ R.103), 2.4\ kbit/s (Recommendations\ R.101, R.105, R.112
and\ R.111, \(sc\ 2), 4.8\ kbit/s (Recommendations\ R.102 and\ R.111, \(sc\ 
2) and 
9.6\ kbit/s (Recommendation\ R.111, \(sc\ 2).
.PP
2.3
56 kbit/s TDM links are realized using envelope interleaving
TDM systems which are defined in Recommendations\ X.55\ [7] and\ X.56\ 
[8]. These systems provide the same tributary channels as in\ 2.2.2. 
.sp 9p
.RT
.LP
.rs
.sp 16P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.PP
2.4
Figure 1/R.100 shows a typical multiplex hierarchy\fR .
.sp 9p
.RT
.LP
.rs
.sp 47P
.ad r
\fBFigure 1/R.100, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
2.5
The capacities of 50 baud channels of 64 and 56\ kbit/s TDM systems are 
shown in Table\ 2/R.100. 
.sp 9p
.RT
.ce
\fBH.T. [T2.100]\fR 
.ce
TABLE\ 2/R.100
.ce
\fB50 baud channel capacities of homogeneous TDM systems\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(120p) | cw(42p) sw(42p) , ^  | c | c.
 {
Recommendation No. of TDM systems
 }	 {
Maximum No. of 50 baud channels
 }
	Transparent	Non\(hytransparent
_
.T&
lw(120p) | cw(42p) | cw(42p) .
R.111, \(sc 1 (64 kbit/s)	240	\(em
_
.T&
cw(48p) | lw(72p) | cw(42p) | cw(42p) , ^  | l | c | c 
^  | l | c | c 
^  | l | c | c 
^  | l | c | c 
^  | l | c | c 
^  | l | c | c 
^  | l | c | c.
 {
X.50 (64 kbit/s)
X.51 (64 kbit/s)
X.55 (56 kbit/s)
or
X.56 (56 kbit/s) 
 }	20 \(mu R.101 (2.4 kbit/s)	\(em	\ 920
	20 \(mu R.112 (2.4 kbit/s)	300	\ 920	10 \(mu R.102 (4.8 kbit/s)	300	\ 920	 {
20 \(mu R.111, \(sc 2 (2.4 kbit/s)
 }	160	\(em	 {
10 \(mu R.111, \(sc 2 (4.8 kbit/s)
 }	160	\(em	 {
\ 5 \(mu R.111, \(sc 2 (9.6 kbit/s)
 }	160	\(em	20 \(mu R.105 (2.4 kbit/s)	\(em	5120 (Note)	80 \(mu R.103 (0.6 kbit/s)	\(em	\ 640
.TE
.LP
\fINote\fR
\ \(em\ Virtual channels.
.nr PS 9
.RT
.ad r
\fBTABLE 2/R.100 [T2.100], p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
2.6
The characteristics of 64 and 56\ kbit/s digital circuit interfaces are 
described in Recommendations\ G.703\ [9] and\ V.36\ [4]. 
.sp 9p
.RT
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	 CCITT Recommendation \fI9600 bits per second modem standardized for use\fR 
\fIon point\(hyto\(hypoint 4\(hywire leased telephone\(hytype circuits\fR 
, Rec.\ V.29. 
.LP
[2]
	CCITT Recommendation \fITransmission requirements of international\fR 
\fIvoice\(hyfrequency telegraph links (at 50, 100 and 200 bauds)\fR , Rec.\ 
H.22. 
.LP
[3]
	CCITT Recommendation \fIPerformance characteristics of PCM channels\fR 
\fIbetween 4\(hywire interfaces at audio frequencies\fR , Rec.\ G.712.
.LP
[4]
	 CCITT Recommendation \fIModems for synchronous data transmission using\fR 
\fI60\(hy108 kHz group band circuits\fR , Rec.\ V.36. 
.LP
[5]
	 CCITT Recommendation \fIFundamental parameters of a multiplexing scheme\fR 
\fIfor the international interface between synchronous data networks\fR 
, 
Rec.\ X.50.
.LP
[6]
	 CCITT Recommendation \fIFundamental parameters of a multiplexing scheme\fR 
\fIfor the international interface between synchronous data networks using\fR 
\fI10\(hybit envelope structure\fR , Rec.\ X.51.
.LP
[7]
	CCITT Recommendation \fIInterface between synchronous data networks\fR 
\fIusing a 6\ +\ 2 envelope structure and single channel per carrier (SCPC)\fR 
\fIsatellite channels\fR , Rec.\ X.55.
.LP
[8]
	CCITT Recommendation \fIInterface between synchronous data networks\fR 
\fIusing an 8\ +\ 2 envelope structure and single channel per carrier (SCPC)\fR 
\fIsatellite channels\fR , Rec.\ X.56.
.LP
[9]
	CCITT Recommendation \fIPhysical/electrical characteristics of\fR 
\fIhierarchical digital interfaces\fR , Rec.\ G.703.
.bp
.sp 2P
.LP
\fBRecommendation\ R.101\fR 
.RT
.sp 2P
.ce 1000
\fBCODE\ AND\ SPEED\ DEPENDENT\ TDM\ SYSTEM\fR 
.EF '%	Fascicle\ VII.1\ \(em\ Rec.\ R.101''
.OF '''Fascicle\ VII.1\ \(em\ Rec.\ R.101	%'
.ce 0
.ce 1000
\fBFOR\ \fR \fBANISOCHRONOUS\ TELEGRAPH\ AND\ DATA\ TRANSMISSION\fR 
.ce 0
.sp 1P
.ce 1000
\fBUSING\ BIT\ INTERLEAVING\fR 
.ce 0
.sp 1P
.ce 1000
\fI(Geneva, 1976; amended at Geneva, 1980,\fR \fIM\*'alaga\(hyTorremolinos, 
1984 and Melbourne, 1988)\fR 
.sp 9p
.RT
.ce 0
.sp 1P
.LP
	The\ CCITT,
.sp 1P
.RT
.sp 1P
.LP
\fIconsidering\fR 
.sp 9p
.RT
.PP
(a) 
that the economic transmission of large numbers of
anisochronous telegraph and data services over a single telephone\(hytype
circuit may be achieved by using time\(hydivision multiplexing (TDM)
techniques;
.PP
(b) 
that the multiplexing system should be capable of
operating as a sub\(hymultiplexer within a higher order TDM hierarchy as 
well as on an analogue telephone\(hytype circuit in association with standard 
data 
modems;
.PP
(c) 
that the codes and speeds used for anisochronous
telegraph and data transmission are well defined, permitting the application 
of simple code\(hydependent multiplexing techniques; 
.PP
(d) 
that code\(hydependent multiplexing provides inherent
regeneration of start\(hystop signals carried by the system;
.PP
(e) 
that, while it is foreseen that the main application would be for telex 
traffic, the multiplexing system should be capable of 
simultaneously transmitting the complete range of standard 
anisochronous
speeds and codes
likely to be required by users;
.PP
(f
) 
that the multiplexing system should be capable of
accepting for transmission all types of telex signals and of regenerating 
those signals at the channel outputs within the tolerances specified in 
the relevant CCITT Recommendations; 
.PP
(g) 
that the multiplexing system should permit the efficient mixing of various 
combinations of anisochronous speeds, codes and signalling 
types in the same transmission system;
.PP
(h) 
that the minimum duration of signal transfer delay
through the TDM system could be achieved by the transmission of interleaved
elements;
.sp 1P
.LP
\fIunanimously declares the view\fR 
.sp 9p
.RT
.PP
that, where 
bit\(hyinterleaved code and speed dependent TDM
systems
are used for 
anisochronous telegraph and data transmission
with an aggregate bit rate of 2400\ bit/s carried either by an analogue
telephone\(hytype circuit or by a higher order TDM, the equipment shall be
constructed to comply with the following standard:
.sp 2P
.LP
\fB1\fR 	\fBSystem capacity\fR 
.sp 1P
.RT
.PP
1.1
The capacity of the system shall be 46 channels at 50\ bauds
(7.5\ units including a stop element of 1.5\ units).
.sp 9p
.RT
.PP
1.2
For other modulation rates two alternatives are allowed.
.sp 2P
.LP
1.2.1
	\fIAlternative\ A\fR 
.sp 1P
.RT
.PP
1.2.1.1
Channels at 75\ bauds (7.5\ units including a stop element of
1.5\ units) shall be accommodated. See \(sc\ 5.5.2 below.
.sp 9p
.RT
.PP
1.2.1.2
Further study is needed to accommodate other modulation
rates.
.bp
.sp 2P
.LP
1.2.2
	\fIAlternative\ B\fR 
.sp 1P
.RT
.PP
1.2.2.1
The modulation rates and character structures shown in
Table\ 1/R.101 shall be accommodated with the capacities indicated for
homogeneous configurations
.
.sp 9p
.RT
.PP
1.2.2.2
The TDM system shall be capable of multiplexing the eight
modulation rates shown in Table\ 1/R.101 simultaneously.
.ce
\fBH.T. [T1.101]\fR 
.ce
TABLE\ 1/R.101
.ce
\fBSystem capacity (alternative B)\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(54p) | cw(60p) sw(60p) | cw(54p) , ^  | c | c | ^ .
Modulation rate  (bauds)	Character structure	 {
Number of channels
(homogeneous configuration)
 }
	Character length  (units)	Stop element  (units)
_
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
\ 50	\ 7.5	1.5	46
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
\ 75	\ 7.5	1.5	30
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
100	\ 7.5 or  10	1.5  1	22
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
110	11	2	22
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
134.5	\ 9	1	15
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
150	10	1	15
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
200	\ 7.5,  10 or  11	1.5  1  2	10
.T&
lw(54p) | lw(60p) | lw(60p) | lw(54p) .
300	10 or  11	1  2	\ 7
_
.TE
.nr PS 9
.RT
.ad r
\fBTABLE 1/R.101 [T1.101], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.sp 5
.sp 2P
.LP
\fB2\fR 	\fBStart\(hystop channel inputs\fR 
.sp 1P
.RT
.PP
2.1
The modulation rate tolerance that shall be accepted on
continuous incoming 50\(hy and 75\(hybaud start\(hystop signals with a 
stop element of 1.4\ units shall be at least \(+- | .4%. 
.sp 9p
.RT
.PP
2.2
When receiving characters at 50 or 75 bauds having nominally
1.5\(hyunit stop elements, the system shall be capable of transmitting without
error, isolated incoming characters that have a one\(hyunit stop element,
occurring at a maximum rate of one per second.
.PP
2.3
The minimum interval between start elements of undistorted
successive continuous characters that may be presented at the channel input
when the nominal modulation rate is 50 or 75\ bauds shall be 145 | /6 or
97 | /9\ ms respectively.
.PP
2.4
There shall be no restriction on the continuous transmission
of all characters specified in \(sc\ 1 above (e.g.\ combination No.\ 32 of
International Telegraph Alphabet No.\ 2) when they are presented at the 
maximum permitted rate. 
.bp
.PP
2.5
The effective net margin on all channel inputs when undistorted
signals are received from a transmitter having a nominal character length 
and rate shall be at least 40%. 
.PP
2.6
At the nominal signalling rate, an input character start
element shall be rejected if equal to or less than 0.4\ units duration 
and shall be accepted if equal to or more than 0.6\ units duration. 
.PP
2.7
Elements corresponding to start polarity (at the distant
multiplexer output) shall be inserted in the aggregate stream in the
case of:
.LP
	a)
	unequipped channels;
.LP
	b)
	equipped but unallocated channels;
.LP
	c)
	open\(hycircuit line condition at the local start\(hystop channel
input.
.PP
2.8
The maximum tolerance on modulation rates other than 50 and 75
bauds shall be\ 1.8%.
.sp 2P
.LP
\fB3\fR 	\fBStart\(hystop channel outputs\fR 
.sp 1P
.RT
.PP
3.1
The maximum degree of gross start\(hystop distortion shall be 3% for all 
permitted modulation rates. 
.sp 9p
.RT
.PP
3.2
The maximum difference possible between the mean modulation
rate of the channel output signals and the nominal modulation rate shall be
0.2%.
.PP
3.3
When characters having a nominal 1.5\(hyunit stop element are
presented at any input rate within the specified range of this Recommendation, 
the minimum stop element duration released at the output shall be 1.25\ 
units. 
.PP
3.4
When characters having a nominal 1\(hy or 2\(hyunit stop element are
presented at any input rate within the specified range of this Recommendation, 
the minimum stop element duration released at the output shall be 0.8 or 
1.8\ units respectively.
.PP
3.5
Channel output shall be controlled as specified below in the
event of recognition of any of the following failure conditions:
.LP
	a)
	carrier loss signalled by the modem (OFF condition
of received line signal detector \(em circuit CT109, Recommendation\ V.24\ 
[1]); 
.LP
	b)
	loss of aggregate signal (defined as a period of 280\ ms
without a transition on the aggregate);
.LP
	c)
	loss of synchronization.
.PP
3.6
Within 4 ms of the recognition of the failures described in
\(sc\ 3.5, the following shall occur to the channel outputs of the affected 
TDM: 
.sp 9p
.RT
.PP
3.6.1
Leased channels \(em two options shall be possible on a per
channel basis:
.LP
	a)
	set to steady start polarity;
.LP
	b)
	set to steady stop polarity;
.PP
3.6.2
Circuit\(hyswitched service \(em two options shall be possible on a
per channel basis:
.LP
	a)
	steady start polarity at the channel output;
.LP
	b)
	 loopback of the channel towards the local end for a period of 5\ \(+-\ 
1\ seconds, after which channel outputs shall revert to steady start 
polarity. Additionally for alternative\ B, the traffic path shall be maintained 
towards the distant multiplexer terminal during this loopback interval. 
.PP
\fINote\fR \ \(em\ The actions taken in case 3.6.2\ a) shall ensure that,
after recognition of failure, no 50\(hybaud channel used for circuit\(hyswitched 
service shall produce an output pulse of stop polarity of longer than 20\ 
ms or a series of 20\(hyms pulses of stop polarity. It should be noted 
that 20\(hyms pulses can cause difficulty with some switching equipment. 
The loopback option in 
3.6.2\ b) is provided in order to avoid clearance of established connections
during short breaks and thus avoid excessive recall attempts.
.bp
.PP
3.7
The affected terminal shall signal its synchronization status to the distant 
terminal in accordance with \(sc\(sc\ 6.3.5 for alternative\ A and\ 6.4.2 
for alternative\ B. The distant terminal shall control its channel outputs 
in 
accordance with \(sc\ 3.6\ above with a delay that shall not exceed 600\ 
ms (measured from the instant of failure), ignoring the propagation time 
of the bearer 
circuit. Alternatively, for alternative\ B, leased channels have the option, 
at the customer's request, of maintaining the traffic path in the unaffected 
direction.
.sp 9p
.RT
.sp 2P
.LP
\fB4\fR 	\fBMultiplexing details\fR 
.sp 1P
.RT
.PP
4.1
Channel interleaving shall be on a bit basis.
.sp 9p
.RT
.PP
4.2
Both start and stop elements of each input character shall be
transmitted through the aggregate.
.PP
4.3
The transfer delay for 50\(hy and 75\(hybaud signals through a pair
of terminals connected back\(hyto\(hyback (excluding the modems) shall 
not exceed 
2.5\ units. This delay shall be measured from the reception of the start
element of a character at an input channel of one terminal until the
corresponding start element is delivered from the output channel of the 
second terminal. 
.sp 2P
.LP
4.4
	\fIAlternative\ A\fR 
.sp 1P
.RT
.PP
4.4.1
Multiplexing details for higher modulation rates remain for   study.
.sp 9p
.RT
.sp 2P
.LP
4.5
	\fIAlternative\ B\fR 
.sp 1P
.RT
.PP
4.5.1
The maximum transfer delay for all other permitted channel
speeds for back\(hyto\(hyback terminals shall not exceed 3.5\ units.
.sp 9p
.RT
.PP
4.5.2
110\(hybaud characters are conveyed on a 100\(hybit/s bearer
channel by transmitting at least one stop element in the aggregate signal.
.PP
4.5.3
134.5\(hybaud characters are conveyed on a 150\(hybit/s bearer
channel by transmitting the necessary filling bits of stop polarity before 
the character start elements in the aggregate signal. 
.sp 2P
.LP
\fB5\fR 	\fBFrame structure\fR 
.sp 1P
.RT
.PP
5.1
A unique subframe of 47\ bits shall be used.
.sp 9p
.RT
.PP
5.2
A 47\(hybit subframe shall consist of one synchronization bit in
the first bit position and 46\ traffic bits.
.PP
5.3
A fundamental frame consisting of two consecutive subframes
shall be used.
.PP
5.4
Two alternative framing arrangements are allowed; however, the
channel numbers used throughout this Recommendation represent the last two
digits of a 4\(hydigit numbering scheme \(hy and are shown in Recommendation\ 
R.114. This channel numbering scheme (see Tables 3/R.101, 4/R.101 
and\ 5/R.101) covers both framing arrangements.
.sp 2P
.LP
5.5
	\fIAlternative\ A\fR 
.sp 1P
.RT
.PP
5.5.1
Two scrambling techniques are used:
.sp 9p
.RT
.PP
5.5.1.1
Alternate frame slots have inverted signal polarity. The
chart of frame structure (see Table\ 2/R.101) indicates the pattern used.
Channels not equipped are transmitted as\ A (start) polarity.
.PP
5.5.1.2
The channels are arranged for external interconnection
with assignment of a sequence of channel numbers (channel\ 1 through
channel\ 46). These channel numbers are distinct from frame slot assignment.
(This is comparable to a VFT's having both a frequency assignment and a 
channel number.) The channel numbering sequence is scrambled with respect 
to the frame slot sequence. This technique is useful not only for ensuring 
a good 
distribution of transitions, but also for simplifying mixed speed
programming.
.bp
.ce
\fBH.T. [T2.101]\fR 
.ce
TABLE\ 2/R.101
.ce
\fBFrame for forty\(hysix 50\(hybaud channels with provision for
.ce
75\(hybaud channels (Alternative A)\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(28p) | cw(28p) | cw(30p) | cw(28p) .
Subframe slot	Channel number	 {
Aggregate polarity corresponding to Z polarity on low\(hyspeed
channel
 }	Channel speed
_
.T&
cw(28p) | cw(58p) | cw(28p) .
\ 1	Not applicable	SYNC
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 2	02	A	50 | ua\d\u)\d
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 3	01	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 4	05	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 5	06	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 6	09	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 7	10	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 8	14	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
\ 9	13	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
10	17	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
11	18	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
12	21	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
13	22	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
14	25	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
15	26	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
16	30	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
17	29	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
18	33	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
19	34	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
20	37	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
21	38	Z	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
22	41	A	50
_
.T&
cw(28p) | cw(28p) | cw(30p) | lw(28p) .
23	42	Z	50
_
.TE
.nr PS 9
.RT
.ad r
\fBTABLE 2/R.101 [T2.101], p. 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
5.5.2
In Table\ 2/R.101, higher speed channels may be substituted
for multiple low\(hyspeed channels. The resulting channel should bear the 
number of the lowest channel replaced. For example, when channels\ 02 and\ 
04 are 
replaced by a 75\(hybaud channel, the 75\(hybaud channel should be known as
channel\ 02. (See Table\ 3/R.101 for the relative numbering of 50\(hy\ 
and 75\(hybaud 
channels.)
.LP
.sp 2
.rs
.sp 43P
.ad r
\fBTABLE 3/R.101, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
5.6
	\fIAlternative\ B\fR 
.sp 1P
.RT
.PP
5.6.1
The channel allocation in the fundamental frame is shown in Table\ 6/R.101 
in matrix form giving the relationship between individual 
low\(hyspeed channels and the corresponding traffic bits. The fundamental 
frame is represented as divided into four groups of 24\ positions. The 
correspondence 
between positions in the matrix structure and bit numbers within the
fundamental frame is shown in the bit number columns. The table also shows 
the distribution of positions within the specific groups for channels of 
different speeds and the corresponding channel numbering. (See also Tables\ 
4/R.101 
and\ 5/R.101.)
.sp 9p
.RT
.LP
.sp 2
.rs
.sp 43P
.ad r
\fBTable 4/R.101, p. 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBTable 5/R.101, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T3.101]\fR 
.T&
lw(38p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) 
| lw(66p) . 
								
.T&
lw(38p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) 
| lw(66p) . 
 {
MONTAGE
Channel number
Group 1
MONTAGE
Channel number
Group 2
MONTAGE
Channel number
Group 3
MONTAGE
Channel number
Group 4
 }								
.T&
lw(38p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
50 100 200 75 150 300 50 100 200 75 150 300 50 100 200 75 150 300 50 100 
200 75 150 300 
.T&
lw(22p) | lw(16p) | cw(10p) | lw(66p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(10p) . 
	0	 {
Synchronization bit
1
01
01
01
01
01
01
2
02
02
02
02
02
02
3
03
03
03
03
03
03
 }																						
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
4
04
04
04
04
04
04
5
05
05
05
05
05
05
6
06
06
06
06
06
06
7
07
07
07
07
07
07
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
8
08
x
x
08
08
x
9
09
09
09
09
09
01
10
10
10
10
10
10
02
11
11
11
11
11
11
03
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
12
12
12
x
12
12
04
13
13
13
01
13
13
05
14
14
14
02
14
14
06
15
15
15
03
15
15
07
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
16
16
16
04
x
x
x
17
17
17
05
17
01
01
18
18
18
06
18
02
02
19
19
19
07
19
03
03
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
20
20
20
x
20
04
04
21
21
21
09
21
05
05
22
22
22
10
22
06
06
23
23
23
11
23
07
07
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
24
24
x
x
24
08
x
25
25
01
01
25
09
01
26
26
02
02
26
10
02
27
27
03
03
27
11
03
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
28
28
04
04
28
12
04
29
29
05
05
29
13
05
30
30
06
06
30
14
06
31
31
07
07
31
15
07
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
								 {
32
32
09
09
01
01
01
33
33
10
10
02
02
02
34
34
11
11
03
03
03
 }																					
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
35
35
12
x
04
04
04
36
36
13
01
05
05
05
37
37
14
02
06
06
06
38
38
15
03
07
07
07
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
39
39
16
04
08
08
x
40
40
17
05
09
09
01
41
41
18
06
10
10
02
42
42
19
07
11
11
03
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
43
43
20
x
12
12
04
44
44
21
09
13
13
05
45
45
22
10
14
14
06
46
46
23
11
15
15
07
 }																												
.TE
.nr PS 9
.RT
.ad r
\fBTable 6/R.101 [T3.101] \ \ 
(\*`a l'italienne), p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T4.101]\fR 
.ce
TABLE\ 7/R.101
.ce
\fBAlternative B channel numbering\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(30p) | cw(30p) | cw(168p) .
Channel rate  (bauds)	 {
Range of channel number \fIn\fR
 }	 {
Subframe slot(s) allocated to channel number \fIn\fR
 }
_
.T&
cw(30p) | cw(30p) | lw(168p) .
\ 50	01\(hy46	\fIn\fR
_
.T&
cw(30p) | cw(30p) | lw(126p) | lw(42p) , ^  | c | l | ^ .
\ 75	01\(hy15	 {
\fIn\fR
and (\fIn\fR
+ 31) from first subframe and
(\fIn\fR
+ 16)
from second subframe
 }	See Notes 1 and 2
	17\(hy31	 {
\fIn\fR
from first subframe and
(\fIn\fR
\(em 16) and (\fIn\fR
+ 15)
from second subframe
 }
_
.T&
cw(30p) | cw(30p) | lw(42p) | lw(126p) , ^  | c | l | ^ .
100	01\(hy07	 {
\fIn\fR
and (\fIn\fR
+ 24)
 }	See Note 3
	09\(hy23	 {
\fIn\fR
and (\fIn\fR
+23)
 }
_
.T&
cw(30p) | cw(30p) | lw(168p) .
150	01\(hy15	 {
\fIn\fR
and (\fIn\fR
+ 16) and (\fIn\fR
+ 31)
 }
_
.T&
cw(30p) | cw(30p) | lw(96p) | lw(72p) , ^  | c | l | ^ .
200	01\(hy07	 {
\fIn\fR
and (\fIn\fR
+ 12) and (\fIn\fR
+ 24) and (\fIn\fR
+ 35)
 }	See Note 3
	09\(hy11	 {
\fIn\fR
and (\fIn\fR
+ 12) and (\fIn\fR
+ 23) and (\fIn\fR
+ 35)
 }
_
.T&
cw(30p) | cw(30p) | lw(168p) .
300	01\(hy07	 {
\fIn\fR
and (\fIn\fR
+ 8) and (\fIn\fR
+ 16) and (\fIn\fR
+ 24) and
(\fIn\fR
+ 31) and (\fIn\fR
+ 39)
 }
.TE
.LP

\fINote\ 1\fR
\ \(em\ At 75 bauds, channel number \fIn\fR
and \fIn\fR
+ 16 are interdependent,
i.e. when channel \fIn\fR
is used for 75 baud traffic, channel\ \fIn\fR
+ 16
must also be used for 75 bauds or remain unallocated.
.LP
\fINote\ 2\fR
\ \(em\ Channel number 16 not used.
.LP
\fINote\ 3\fR
\ \(em\ Channel number 08 not used.
.LP
\fINote\ 4\fR
\ \(em\ 110 and 134.5\(hybaud signals shall be transmitted on 100 and 150 bit/s bearer channels respectively and restituted with appropriate rate at the
channel output. See also \(sc\(sc\ 4.5.2 and 4.5.3 (Alternative B).
.nr PS 9
.RT
.ad r
\fBTable 7/R.101 [T4.101], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.sp 2
.PP
\fINote\ 1\fR \ \(em\ For all speeds other than 75\ bauds, the second
subframe in the fundamental frame is a repetition of the first subframe.
.PP
\fINote\ 2\fR \ \(em\ In each subframe one position within group\ 1 is skipped,
i.e.\ allocated zero time in the aggregate signal.
.RT
.PP
5.6.2
Substitution of higher speed channels into a homogeneous
50\(hybaud system configuration shall be made as follows:
.sp 9p
.RT
.LP
	2\ \(mu\ 75\(hybaud\ channels
	replaces 3\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 100\(hy\ or\ 110\(hybaud\ channel
	replaces 2\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 150\(hy\ or\ 134.5\(hybaud\ channel
	replaces 3\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 200\(hybaud\ channel
	replaces 4\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 300\(hybaud\ channel
	replaces 6\ \(mu\ 50\(hybaud channels
.PP
5.6.3
All bits from groups\ 3 and\ 4 shall give inverted polarity.
.sp 9p
.RT
.PP
5.6.4
The first, third and fifth bits of the synchronization
pattern are contained in the first subframe. The second, fourth and sixth 
bits are contained in the second subframe (see \(sc\ 6.4.2). 
.bp
.sp 2P
.LP
\fB6\fR 	\fBSynchronizing\fR 
.sp 1P
.RT
.PP
6.1
The system shall not lose synchronism more than once per hour for a randomly 
distributed error rate of one part in\ 10\u3\d. 
.sp 9p
.RT
.PP
6.2
Two synchronizing arrangements are allowed as follows on \(sc\(sc\ 6.3
and\ 6.4.
.sp 2P
.LP
6.3
	\fIAlternative\ A\fR 
.sp 1P
.RT
.PP
6.3.1
The synchronizing bits shall be alternated between\ 1 and\ 0 in successive 
subframes during normal traffic periods. 
.sp 9p
.RT
.PP
6.3.2
The system shall declare loss of synchronism when
7\ synchronizing bits are detected in error during a period of\ 1.5
to\ 2\ seconds.
.PP
6.3.3
With two terminals connected back\(hyto\(hyback (excluding the
modems), one terminal shall be capable of detecting loss of synchronism 
within 280\ ms when its received aggregate signals are replaced by either 
steady start or steady stop polarity. 
.PP
6.3.4
Under the conditions in \(sc\ 6.1 above, after loss of
synchronism has been recognized and the receive aggregate signals have been
restored, the average time that may be taken for the terminal concerned to
resynchronize and to connect normal data through to the low\(hyspeed channel
outputs shall be less than 900\ ms.
.PP
6.3.5
When one terminal recognizes loss of synchronism:
.LP
	a)
	traffic transmitted to the other terminal shall be
interrupted immediately;
.LP
	b)
	 the changes shown in Figures\ 1/R.101 and\ 2/R.101 shall occur in the 
synchronizing pattern. 
.sp 2P
.LP
6.4
	\fIAlternative\ B\fR 
.sp 1P
.RT
.PP
6.4.1
A sync frame is defined as a sequence of three consecutive
fundamental frames (i.e.\ six consecutive subframes) containing a
synchronization word that consists of six\ equidistantly spaced bits.
.sp 9p
.RT
.PP
6.4.2
The normal sync pattern transmitted when the TDM terminal
receiver is correctly synchronized will be 100010. When the receiver is 
out of synchronism the transmitted pattern shall be 011101 (see \(sc\ 6.4.5 
below). The 
changeover shall only occur at the end of a sync frame.
.PP
6.4.3
Loss of synchronism is defined when three consecutive
synchronization patterns are received in error.
.PP
6.4.4
When the received aggregate signal is replaced by steady
start or steady stop polarity, the receiver terminal shall be capable of
detecting loss of synchronism within 280\ ms.
.PP
6.4.5
With two terminals connected back\(hyto\(hyback, loss of
synchronism in one terminal shall be indicated at the other terminal within
240\ ms, by inversion of the normal synchronization pattern. (See \(sc\ 6.4.2
above.)
.PP
6.5
Receipt of the inverted sync pattern shall cause the terminal to force 
the aggregate traffic bits to the polarities corresponding to: 
.sp 9p
.RT
.LP
	a)
	steady start at the start\(hystop channel input for channels
that are used for circuit\(hyswitched service and that are in the free\(hyline
condition;
.LP
	b)
	steady stop at the start\(hystop channel input for all other
channels,
.LP
that is, both transmitted in accordance with \(sc\ 5.6.3 above.
.PP
6.6
Synchronism is defined as achieved when:
.sp 9p
.RT
.LP
	a)
	 six identical synchronization patterns (i.e.\ six normal or six inverted 
synchronization patterns) have been consecutively received on a 
single bit position without error; and
.LP
	b)
	within the same period, two or more consecutive identical
synchronization patterns (i.e.\ normal or inverted sense) have not been 
received on any of the other bit positions in the 47\(hybit subframe. 
.LP
The sense of the patterns in a) and b) may be different.
.bp
.LP
.rs
.sp 47P
.ad r
\fBFIGURE 1/R.101, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 26P
.ad r
\fBFIGURE 2/R.101, p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
6.7
If condition a) in \(sc\ 6.6 above is fulfilled while condition
b) is not:
.sp 9p
.RT
.LP
	a)
	the search for synchronism is continued in the terminal
concerned; and
.LP
	b)
	this terminal shall force the transmitted aggregate
traffic bits to the polarities indicated in \(sc\ 6.5 above.
.PP
6.8
Under the conditions in \(sc\ 6.1 above, after loss of
synchronism has been recognized and the aggregate signals have been restored, 
the average time that may be taken for the terminal concerned to resynchronize 
and to connect normal data through to the low\(hyspeed channel outputs 
shall be 
less than 960\ ms, excluding all transmission delays external to the R.101 
TDM terminal equipment. 
.sp 9p
.RT
.sp 2P
.LP
\fB7\fR 	\fBTelex signalling\fR 
.sp 1P
.RT
.PP
7.1
Specifications for the signals used to establish, to clear and to control 
telex calls are laid down in Recommendations\ U.1 (types A and\ B), 
U.11 (type\ C) and U.12 (type D). Recommendation U.25 lists the modes of
both\(hyway telex signalling on a single circuit and the signalling combinations 
on a given aggregate that a TDM terminal shall be capable of 
handling.
.sp 9p
.RT
.PP
7.2
Recommendation U.25 also lays down the tolerances on the
control signals from a TDM terminal to telex and vice versa.
.sp 2P
.LP
\fB8\fR 	\fBAggregate signals and interface\fR 
.sp 1P
.RT
.PP
8.1
The tolerance on the modulation rate of the send aggregate
signals of the TDM system shall be \(+- | .01%.
.sp 9p
.RT
.PP
8.2
The maximum degree of isochronous distortion of the send
aggregate signals of the TDM system shall be\ 4%.
.PP
8.3
The effective net margin of the aggregate receiver of the TDM
system shall be at least\ 40%.
.bp
.PP
8.4
When the TDM system is operated with an aggregate speed of
2400\ bit/s over an international analogue telephone\(hytype circuit, it is
preferred that a modem complying with the appropriate aspects of the Series\ 
V Recommendations be employed. 
.PP
8.5
The electrical interface conditions and control signals between
the TDM system and the bearer circuit shall comply with the appropriate
Recommendations in the\ V and X\ Series.
.sp 2P
.LP
\fB9\fR 	\fBSystem clock arrangements\fR 
.sp 1P
.RT
.PP
9.1
The TDM system shall be capable of operating with either an
internal or external transmit clock.
.sp 9p
.RT
.PP
9.2
In the event of the failure of an external clock that may be
used for the TDM transmit, the TDM shall continue to function locally for
maintenance purposes using its own internal clock.
.PP
9.3
The receive clock for the TDM terminal shall be provided by the
bearer circuit or higher order multiplex.
.PP
9.4
In the event of the failure of an external clock that may be
used for the TDM receive, the TDM shall continue to function locally for
maintenance purposes using its own internal clock.
.PP
9.5
The internal clock provided in the TDM terminal should have an
accuracy of\ 0.01%.
.sp 2P
.LP
\fB10\fR 	\fBSystem maintenance, control and alarms\fR 
.sp 1P
.RT
.PP
10.1
One 50\(hybaud channel may be allocated (on an optional basis) for maintenance 
purposes, where possible on a separate system using a parallel 
route. Where this option is exercised, channels 16 or 24 (subframe slots\ 16
or\ 24) in alternative\ B equipment or channel\ 45 (subframe slot\ 24) in
alternative\ A equipment are preferred to minimize the effect on the derivation 
of higher\(hyrate channels. 
.sp 9p
.RT
.PP
10.2
If the internal (logic) power supply of the TDM terminal fails
and an external telegraph battery supply is employed, all local start\(hystop
channel outputs shall be controlled to start polarity.
.PP
10.3
It shall be possible to reallocate individual start\(hystop channels for 
different services without removing the TDM terminal from service. 
.sp 2P
.LP
\fB11\fR 	\fBLink transmission system quality indicator\fR 
.sp 1P
.RT
.PP
11.1
The synchronizing bits in the alternative\ A or\ B structures shall be 
monitored (on an optional basis) to provide information on the error rate 
of the aggregate. 
.sp 9p
.RT
.PP
The implementation of this optional mesurement should be such that the 
error rate on the synchronizing bits is supervised continuously and an 
alarm is issued when a preselected limit has been reached.
.PP
The alarm limits should be at least one faulty bit every 10\u3\d,
10\u4\d or 10\u5\d\ bits.
.RT
.PP
11.2
For alternative\ A, the occurrence of an incorrect synchronizing
bit (when the TDM is in synchronism) should be signalled to an internal or
external equipment (see Note\ 1). Alternative\ B is for further study.
.PP
11.3
The interface between the telegraph muldex and the measuring
equipment should be in accordance with national requirements.
.PP
11.4
Between the moment at which the TDM system has declared loss of
synchronism and restoration of the latter, the invalid synchronization pulse
shall not be generated.
.sp 2P
.LP
\fB12\fR 	\fBLink transmission system availability indicator\fR 
.sp 1P
.RT
.PP
12.1
The loss of synchronism of a synchronized TDM in alternative\ A
or\ B shall be monitored (on an optional basis) to provide an indication 
of the transmission system availability. 
.bp
.sp 9p
.RT
.PP
12.2
The interface between the telegraph muldex and the measuring
equipment (see Note\ 2) giving the out\(hyof\(hyservice status should be 
in accordance with national requirements. 
.LP
\fINote\ 1\fR \ \(em\ The external equipment may take the form of a simple
indicating device or a computer system. The \*Qdead time\*U of the device 
may be 
20\ ms, 150\ ms, 1000\ ms or a multiple of the (sub) frame length, this value
being left for further study.
.LP
Wherever possible the error count values should be compared with the
Recommendation\ R.54 requirement (one character in error for the complete
transmission system in 100 | 00, characters).
.LP
Alarm values of a high count number in excess of the above criteria or
a large deviation from a normal count value shall be advised to the
corresponding Administration.
.LP
\fINote\ 2\fR \ \(em\ A measurement of unavailability (with respect to 
transmission system quality) includes breaks due to failure of transmission 
equipment and 
transmission propagation anomalies. The external equipment may take the 
form of a simple indicating device or a computer system. The \*Qdead time\*U 
of the 
equipment shall be 300\ ms or 1000\ ms, the value being left for further study.
.LP
Wherever possible the long term availability shall be in accordance
with CCIR Recommendation\ 557, namely\ 99.7%. It is recognized in this CCIR
Recommendation, that in practice the objectives may fall in the range\ 
99.5 to 99.9%, this value being left for further study. 
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCITT Recommendation \fIList of definitions for interchange circuits\fR 
\fIbetween data terminal equipment and data circuit terminating equipment\fR ,
Rec.\ V.24.
.LP
[2]
	CCITT Recommendation \fIOperational provisions for the international\fR 
\fIpublic telegram service\fR , Rec.\ F.1, \(sc\ C8.
\v'1P'
.sp 2P
.LP
\fBRecommendation\ R.102\fR 
.RT
.sp 2P
.ce 1000
\fB4800\ BIT/S\ \fR \fBCODE\ AND\ SPEED\fR 
.EF '%	Fascicle\ VII.1\ \(em\ Rec.\ R.102''
.OF '''Fascicle\ VII.1\ \(em\ Rec.\ R.102	%'
.ce 0
.ce 1000
\fBDEPENDENT\ AND\ HYBRID\ TDM\ SYSTEMS\fR \fB\ FOR\ ANISOCHRONOUS\fR 
.ce 0
.sp 1P
.ce 1000
\fBTELEGRAPH\ AND\ DATA\ TRANSMISSION\ USING\ BIT\ INTERLEAVING\fR 
.ce 0
.sp 1P
.ce 1000
\fI(Malaga\(hyTorremolinos, 1984; modified at Melbourne, 1988)\fR 
.sp 9p
.RT
.ce 0
.sp 1P
.LP
	The\ CCITT,
.sp 1P
.RT
.sp 1P
.LP
\fIconsidering\fR 
.sp 9p
.RT
.PP
(a) 
that there is a demand for a bit\(hyinterleaved code and
speed dependent TDM system for 
anisochronous telegraph and data
transmission
using an aggregate bit rate of 4800\ bit/s;
.PP
(b) 
that an increase of the economical transmission of large numbers of anisochronous 
telegraph and data signals, especially those of higher modulation rates 
e.g. 300\ bauds, can be achieved by doubling the system 
capacity normally carried over a code and speed dependent TDM using an
aggregate bit rate of 2400\ bit/s;
.PP
(c) 
that the doubling of system capacity should be based on
the already well defined time division multiplexing (TDM) technique used for
the multiplexing system according to Recommendation\ R.101 retaining the 
frame structure of alternative\ B; 
.PP
(d) 
that unit modularity, operation and maintenance should
best be rationalized for both the basic Recommendation\ R.101 (alternative\ B)
TDM and the expanded multiplexing system with the higher aggregate bit rate;
.bp
.PP
(e) 
that the expanded multiplexing system should permit the
accommodation of code\(hydependent and code\(hyindependent (transparent) 
channels 
using the TDM hybrid technique according to Recommendation\ R.112;
.PP
(f
) 
that the expanded multiplexing system should permit the accommodation of 
new facilities emerging in the future, 
.sp 1P
.LP
\fIunanimously declares the view\fR 
.sp 9p
.RT
.PP
that, where bit\(hyinterleaved code and speed dependent TDM systems with 
the provision for a limited use of code\(hyindependent (transparent) channels 
are used for anisochronous telegraph and data transmission with an aggregate 
bit rate of 4800\ bit/s carried either by an analogue telephone\(hytype 
circuit or by a higher order TDM, the equipment shall be constructed as 
an expanded 
multiplexing system to the basic Recommendation\ R.101 (alternative\ B) TDM to
comply with the following standard:
.sp 2P
.LP
\fB1\fR 	\fBSystem capacity\fR 
.sp 1P
.RT
.PP
1.1
The capacity of the system shall be 92 channels at 50 bauds
(7.5 units including a stop element of 1.5\ units).
.sp 9p
.RT
.PP
1.2
For other modulation rates see Table 1/R.102.
.sp 9p
.RT
.PP
1.2.1
The modulation rates and character structures shown in
Table 1/R.102 shall be accommodated with the capacities indicated for
homogeneous configurations.
.ce
\fBH.T. [T1.102]\fR 
.ce
TABLE\ 1/R.102
.ce
\fBSystem capacity\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(48p) | cw(42p) sw(48p) sw(42p) | cw(48p) , ^  | c s | ^ , ^  | c | c | c | c.
Modulation Rate  (bauds)	Code dependent channels	Code independent  channels
		Character structure
	Character length  (units)	Stop element  (units)	 {
Number of channels
(homogeneous configuration)
 }	 {
Number of channels
(homogeneous configuration)
 }
_
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
\ 50	\ 7.5	1.5	92	30
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
\ 75	\ 7.5	1.5	46	\(em
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
100	\ 7.5 or  10	1.5  1	46	15
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
110	11	2	46	\(em
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
134.5	\ 9	1	30	\(em
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
150	10	1	30	\(em
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
200	\ 7.5,  10 or  11	1.5  1  2	22	\ 7
.T&
lw(48p) | lw(42p) | lw(48p) | cw(42p) | cw(48p) .
300	10 or  11	1  2	15	\(em
.TE
.LP
\fINote\fR
\ \(em\ The system capacity for code\(hyindependent channels using the TDM
hybrid technique according to Recommendation R.112 is not covered by this
table.
.nr PS 9
.RT
.ad r
\fBTable 1/R.102 [T1.102], p. \fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
1.2.2
The TDM system shall be capable of multiplexing the eight
modulation rates shown in Table 1/R.102 simultaneously.
.PP
1.2.3
The TDM system shall provide for a limited use of transparent
channels. In using the TDM hybrid technique, the system capacity and the
overall characteristics of the code\(hyindependent channel from the channel 
input to the channel output shall be in accordance with Recommendation\ 
R.112. 
.PP
\fINote\fR \ \(em\ The overall characteristics of code\(hy and speed\(hydependent 
channels are the subject of this Recommendation and are specified in the 
following clauses.
.sp 2P
.LP
\fB2\fR 	\fBStart\(hystop channel\fR \fB inputs\fR 
.sp 1P
.RT
.PP
2.1
The modulation rate tolerance that shall be accepted on continuous incoming 
50\(hy and 75\(hybaud start\(hystop signals with a stop element of 1.4\ 
units 
shall be at least\ \(+- | .4%.
.sp 9p
.RT
.PP
2.2
When receiving characters at 50 or 75 bauds having nominally
1.5\(hyunit stop elements, the system shall be capable of transmitting without
error, isolated incoming characters that have a one\(hyunit stop element, 
occuring at a maximum rate of one per second. 
.PP
2.3
The minimum interval between start elements of undistorted
successive continuous characters that may be presented at the channel input
when the nominal modulation rate is 50 or 75\ bauds shall be 145 | /6 or
97 | /9\ ms respectively.
.PP
2.4
There shall be no restriction on the continuous transmission
of all characters specified in \(sc\ 1 above (e.g.\ combination No.\ 32 of
International Telegraph Alphabet No.\ 2) when they are presented at the 
maximum permitted rate. 
.PP
2.5
The effective net margin on all channel inputs when undistorted
signals are received from a transmitter having a nominal character length 
and rate shall be at least\ 40%. 
.PP
2.6
At the nominal signalling rate, an input character start
element shall be rejected if equal to or less than 0.4\ units duration 
and shall be accepted if equal to or more than 0.6\ units duration. 
.PP
2.7
Elements corresponding to start polarity (at the distant
multiplexer output) shall be inserted in the aggregate stream in the case
of:
.LP
	a)
	unequipped channels;
.LP
	b)
	equipped but unallocated channels;
.LP
	c)
	open\(hycircuit line condition at the local start\(hystop channel  input.
.PP
2.8
The maximum tolerance on modulation rates other than 50 and 75
bauds shall be\ 1.8%.
.sp 2P
.LP
\fB3\fR 	\fBStart\(hystop channel\fR \fB outputs\fR 
.sp 1P
.RT
.PP
3.1
The maximum degree of gross start\(hystop distortion shall be 3% for all 
permitted modulation rates. 
.sp 9p
.RT
.PP
3.2
The maximum difference possible between the mean modulation
rate of the channel output signals and the nominal modulation rate shall
be\ 0.2%.
.PP
3.3
When characters having a nominal 1.5\(hyunit stop element are
presented at any input rate within the specified range of this Recommendation, 
the minimum stop element duration released at the output shall be 1.25\ 
units. 
.PP
3.4
When characters having a nominal 1\(hy or 2\(hyunit stop element are
presented at any input rate within the specified range of this Recommendation, 
the minimum stop element duration released at the output shall be 0.8 or 
1.8\ units respectively.
.bp
.PP
3.5
Channel output shall be controlled as specified below in the
event of recognition of any of the following failure conditions:
.sp 9p
.RT
.LP
	a)
	carrier loss signalled by the modem (OFF condition
of received line signal detector \(em circuit CT109, Recommendation\ V.24\ 
[1]); 
.LP
	b)
	loss of aggregate signal (defined as a period of 280\ ms
without a transition on the aggregate);
.LP
	c)
	loss of synchronization.
.PP
3.6
Within 4 ms of the recognition of the failures described in
\(sc\ 3.5, the following shall occur to the channel outputs of the affected 
TDM: 
.sp 9p
.RT
.PP
3.6.1
Leased channels \(em two options shall be possible on a per
channel basis:
.LP
	a)
	set to steady start polarity;
.LP
	b)
	set to steady stop polarity;
.PP
3.6.2
Circuit\(hyswitched service \(em two options shall be possible on a
per channel basis:
.LP
	a)
	steady start polarity at the channel output;
.LP
	b)
	 loopback of the channel towards the local end for a period of 5\ \(+-\ 
1\ seconds, after which channel outputs shall revert to steady start 
polarity. Additionally, the traffic path shall be maintained towards the
distant multiplexer terminal during this loopback interval.
.PP
\fINote\fR \ \(em\ The actions taken in case 3.6.2\ a) shall ensure that,
after recognition of failure, no 50\(hybaud channel used for circuit\(hyswitched 
service shall produce an output pulse of stop polarity of longer than 20\ 
ms or a series of 20\(hyms pulses of stop polarity. It should be noted 
that 20\(hyms pulses can cause difficulty with some switching equipment. 
The loopback option 
in\ 3.6.2\ b) is provided in order to avoid clearance of established connections 
during short breaks and thus avoid excessive recall attempts. 
.PP
3.7
The affected terminal shall signal its synchronization status to the distant 
terminal in accordance with \(sc\ 6.4. The distant terminal shall 
control its outputs in accordance with \(sc\ 3.6\ above with a delay that 
shall not exceed 600\ ms (measured from the instant of failure), ignoring 
the propagation time of the bearer circuit. Alternatively, leased channels 
have the option, at the customer's request, of maintaining the traffic 
path in the unaffected 
direction.
.sp 9p
.RT
.sp 2P
.LP
\fB4\fR 	\fBMultiplexing details\fR 
.sp 1P
.RT
.PP
4.1
Channel interleaving shall be on a bit basis.
.sp 9p
.RT
.PP
4.2
Both start and stop elements of each input character shall be
transmitted through the aggregate.
.PP
4.3
The transfer delay for 50\(hy and 75\(hybaud signals through a pair
of terminals connected back\(hyto\(hyback (excluding the modems) shall 
not exceed 
2.5\ units. This delay shall be measured from the reception of the start
element of a character at an input channel of one terminal until the
corresponding start element is delivered from the output channel of the 
second terminal. 
.PP
4.4
The maximum transfer delay for all other permitted channel
speeds for back\(hyto\(hyback terminals shall not exceed 3.5\ units.
.PP
4.5
75\(hybaud characters are conveyed on a 100\(hybit/s bearer channel by 
transmitting filling bits in each character following element numbers\ 
2 
and\ 5\ [2].
.PP
4.6
110\(hybaud characters are conveyed on a 100\(hybit/s bearer
channel by transmitting at least one stop element in the aggregate signal.
.PP
4.7
134.5\(hybaud characters are conveyed on a 150\(hybit/s bearer
channel by transmitting the necessary filling bits of stop polarity before 
the character start elements in the aggregate signal. 
.bp
.sp 2P
.LP
\fB5\fR 	\fBFrame structure\fR 
.sp 1P
.RT
.PP
5.1
A unique subframe of 47\ bits shall be used.
.sp 9p
.RT
.PP
5.2
A 47\(hybit subframe shall consist of one synchronization bit in
the first bit position and 46\ traffic bits.
.PP
5.3
A fundamental frame consisting of two consecutive subframes
shall be used.
.PP
5.4
One framing arrangement is allowed. The channel numbers used
throughout this Recommendation represent the last two digits of a 4\(hydigit
numbering scheme \(em\ the first two digits are shown in 
Recommendation\ R.114. This channel allocation scheme is shown in Table\ 
2/R.102 and in Table\ 3/R.102. 
.PP
Table 4/R.102 shows the channel allocation of 50, 100 and 200\ baud code 
independent channels using the TDM hybrid technique according to 
Recommendation\ R.112.
.PP
5.5
The channel allocation in the fundamental frame is shown in
Table\ 5/R.102 in matrix form giving the relationship between individual
low\(hyspeed channels and the corresponding traffic bits. The fundamental 
frame is represented as divided into four groups of 24\ positions. The 
correspondence 
between positions in the matrix structure and bit numbers within the
fundamental frame is shown in the bit number columns. The table also shows 
the distribution of positions within the specific groups for channels of 
different speeds and the corresponding channel numbering. (See also Tables\ 
2/R.102 
and\ 3/R.102.)
.sp 9p
.RT
.PP
\fINote\ 1\fR \ \(em\ For all speeds other than 50 and 150\ bauds, the 
second subframe in the fundamental frame is a repetition of the first subframe. 
.PP
\fINote\ 2\fR \ \(em\ In each subframe one position within group\ 1 is skipped,
i.e.\ allocated zero time in the aggregate signal.
.RT
.PP
5.6
Substitution of higher speed channels into a homogeneous
50\(hybaud system configuration shall be made as follows:
.sp 9p
.RT
.LP
	1\ \(mu\ 75\(hy\ or\ 100\(hy\ or\ 110\(hybaud\ channel
	replaces 2\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 150\(hy\ or\ 134.5\(hybaud\ channel
	replaces 3\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 200\(hybaud\ channel
	replaces 4\ \(mu\ 50\(hybaud channels
.LP
	1\ \(mu\ 300\(hybaud\ channel
	replaces 6\ \(mu\ 50\(hybaud channels
.PP
5.7
All bits from groups\ 3 and\ 4 shall give inverted polarity.
.sp 9p
.RT
.PP
5.8
The first, third and fifth bits of the synchronization
pattern are contained in the first subframe. The second, fourth and sixth 
bits are contained in the second subframe (see \(sc\ 6.4). 
.sp 2P
.LP
\fB6\fR 	\fBSynchronizing\fR 
.sp 1P
.RT
.PP
6.1
The system shall not lose synchronism more than once per hour for a randomly 
distributed error rate of one part in\ 10\u3\d. 
.sp 9p
.RT
.PP
6.2
One synchronizing arrangement is allowed as described in \(sc\(sc\ 6.3
through\ 6.11.
.PP
6.3
A sync frame is defined as a sequence of three consecutive
fundamental frames (i.e.\ six consecutive subframes) containing a
synchronization word that consists of six\ equidistantly spaced bits.
.PP
6.4
The normal sync pattern transmitted when the TDM terminal
receiver is correctly synchronized will be 100010. When the receiver is 
out of synchronism the transmitted pattern shall be 011101 (see \(sc\ 6.7 
below). The 
changeover shall only occur at the end of a sync frame.
.PP
6.5
Loss of synchronism is defined when three consecutive
synchronization patterns are received in error.
.PP
6.6
When the received aggregate signal is replaced by steady
start or steady stop polarity, the receiver terminal shall be capable of
detecting loss of synchronism within 140\ ms.
.PP
6.7
With two terminals connected back\(hyto\(hyback, loss of
synchronism in one terminal shall be indicated at the other terminal within
120\ ms, by inversion of the normal synchronization pattern. (See \(sc\ 
6.4 above.) 
.PP
6.8
Receipt of the inverted sync pattern shall cause the terminal
to force the aggregate traffic bits to the polarities corresponding to:
.LP
	a)
	steady start at the start\(hystop channel input for channels
that are used for circuit\(hyswitched service and that are
in the free\(hyline condition;
.LP
	b)
	steady stop at the start\(hystop channel input for all other
channels,
.LP
that is, both transmitted in accordance with \(sc\ 5.7 above.
.bp
.LP
.rs
.sp 47P
.ad r
\fBTable 2/R.102, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBTable 3/R.102, p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBTable 4/R.102, p. 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T2.102]\fR 
.T&
lw(38p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) 
| lw(66p) . 
								
.T&
lw(38p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) | lw(66p) | lw(10p) 
| lw(66p) . 
 {
Bit No.
Channel number
Group 1
Bit No.
Channel number
Group 2
Bit No.
Channel number
Group 3
Bit No.
Channel number
Group 4
 }								
.T&
lw(38p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
50 100 200 \(em 150 300 50 100 200 \(em 150 300 50 100 200 \(em 150 300 
50 100 200 \(em 150 300 
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
0
s
s
s
\(em
s
s
1
1
1
1
\(em
1
1
2
2
2
2
\(em
2
2
3
3
3
3
\(em
3
3
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
4
4
4
4
\(em
4
4
5
5
5
5
\(em
5
5
6
6
6
6
\(em
6
6
7
7
7
7
\(em
7
7
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
8
8
8
\fIx\fR
\(em
8
8
9
9
9
9
\(em
9
9
10
10
10
10
\(em
10
10
11
11
11
11
\(em
11
11
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
12
12
12
12
\(em
12
12
13
13
13
13
\(em
13
13
14
14
14
14
\(em
14
14
15
15
15
15
\(em
15
15
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
16
16
16
16
\(em
\fIx\fR
\fIx\fR
17
17
17
17
\(em
17
1
18
18
18
18
\(em
18
2
19
19
19
19
\(em
19
3
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
20
20
20
20
\(em
20
4
21
21
21
21
\(em
21
5
22
22
22
22
\(em
22
6
23
23
23
23
\(em
23
7
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
24
24
24
\fIx\fR
\(em
24
8
25
25
25
1
\(em
25
9
26
26
26
2
\(em
26
10
27
27
27
3
\(em
27
11
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
28
28
28
4
\(em
28
12
29
29
29
5
\(em
29
13
30
30
30
6
\(em
30
14
31
31
31
7
\(em
31
15
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
								 {
32
32
32
9
\(em
1
1
33
33
33
10
\(em
2
2
34
34
34
11
\(em
3
3
 }																					
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
35
35
35
12
\(em
4
4
36
36
36
13
\(em
5
5
37
37
37
14
\(em
6
6
38
38
38
15
\(em
7
7
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
39
39
39
16
\(em
8
8
40
40
40
17
\(em
9
9
41
41
41
18
\(em
10
10
42
42
42
19
\(em
11
11
 }																												
.T&
lw(22p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) 
| lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | 
lw(10p) | lw(10p) | lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) 
| lw(10p) | lw(16p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) | lw(10p) . 
	 {
43
43
43
20
\(em
12
12
44
44
44
21
\(em
13
13
45
45
45
22
\(em
14
14
46
46
46
23
\(em
15
15
 }																												
.TE
.nr PS 9
.RT
.ad r
\fBTable 5/R.102 [T2.102] A L'ITALIENNE, p. 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.PP
6.9
Synchronism is defined as achieved when:
.sp 9p
.RT
.LP
	a)
	 six identical synchronization patterns (i.e.\ six normal or six inverted 
synchronization patterns) have been consecutively received on a 
single bit position without error; and
.LP
	b)
	within the same period, two or more consecutive identical
synchronization patterns (i.e.\ normal or inverted sense) have not been 
received on any of the other bit positions in the 47\(hybit subframe. 
.LP
The sense of the patterns in a) and b) may be different.
.PP
6.10
If condition a) in \(sc\ 6.9 above is fulfilled while condition
b) is not:
.sp 9p
.RT
.LP
	a)
	the search for synchronism is continued in the terminal
concerned; and
.LP
	b)
	this terminal shall force the transmitted aggregate
traffic bits to the polarities indicated in \(sc\ 6.8 above.
.PP
6.11
Under the conditions in \(sc\ 6.1 above, after loss of
synchronism has been recognized and the aggregate signals have been restored, 
the average time that may be taken for the terminal concerned to resynchronize 
and to connect normal data through to the low\(hyspeed channel outputs 
shall be 
less than 480\ ms, excluding all transmission delays external to the
Recommendation\ R.102 TDM terminal equipment.
.sp 9p
.RT
.sp 2P
.LP
\fB7\fR 	\fBTelex signalling\fR 
.sp 1P
.RT
.PP
7.1
Specifications for the signals used to establish, to clear and to control 
telex calls are laid down in Recommendations\ U.1 (types A and\ B), 
U.11 (type\ C) and U.12 (type D). Recommendation U.25 lists the modes of
both\(hyway telex signalling on a single circuit and the signalling combinations 
on a given aggregate that a TDM terminal shall be capable of handling. 
.sp 9p
.RT
.PP
7.2
Recommendation U.25 also lays down the tolerances on the
control signals from a TDM terminal to telex and vice versa.
.sp 2P
.LP
\fB8\fR 	\fBAggregate signals and interface\fR 
.sp 1P
.RT
.PP
8.1
The tolerance on the modulation rate of the send aggregate
signals of the TDM system shall be \(+- | .01%.
.sp 9p
.RT
.PP
8.2
The maximum degree of isochronous distortion of the send
aggregate signals of the TDM system shall be\ 4%.
.PP
8.3
The effective net margin of the aggregate receiver of the TDM
system shall be at least\ 40%.
.PP
8.4
When the TDM system is operated with an aggregate speed of
4800\ bit/s over an international analogue telephone\(hytype circuit, it is
preferred that a modem complying with the appropriate aspects of the Series\ 
V Recommendations be employed. 
.PP
8.5
The electrical interface conditions and control signals between
the TDM system and the bearer circuit shall comply with the appropriate
Recommendations in the\ V and X\ Series.
.sp 2P
.LP
\fB9\fR 	\fBSystem clock arrangements\fR 
.sp 1P
.RT
.PP
9.1
The TDM system shall be capable of operating with either an
internal or external transmit clock.
.sp 9p
.RT
.PP
9.2
In the event of the failure of an external clock that may be
used for the TDM transmit, the TDM shall continue to function locally for
maintenance purposes using its own internal clock.
.PP
9.3
The receive clock for the TDM terminal shall be provided by the
bearer circuit or higher order multiplex.
.PP
9.4
In the event of the failure of an external clock that may be
used for the TDM receive, the TDM shall continue to function locally for
maintenance purposes using its own internal clock.
.PP
9.5
The internal clock provided in the TDM terminal should have an
accuracy of\ 0.01%.
.bp
.sp 2P
.LP
\fB10\fR 	\fBSystem maintenance, control and alarms\fR 
.sp 1P
.RT
.PP
10.1
One 50\(hybaud channel may be allocated (on an optional basis) for maintenance 
purposes, where possible on a separate system using a parallel 
route. Where this option is exercised, channels 16 or 24 (subframe slots\ 16
or\ 24) are preferred to minimize the effect on the derivation
of higher\(hyrate channels.
.sp 9p
.RT
.PP
10.2
If the internal (logic) power supply of the TDM terminal fails
and an external telegraph battery supply is employed, all local start\(hystop
channel outputs shall be controlled to start polarity.
.PP
10.3
It shall be possible to reallocate individual start\(hystop
channels for different services without removing the TDM terminal from
service.
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCITT Recommendation \fIList of definitions for interchange circuits\fR 
\fIbetween data terminal equipment and data circuit terminating equipment\fR ,
Rec.\ V.24.
.LP
[2]
	CCITT Recommendation \fIOperational provisions for the international\fR 
\fIpublic telegram service\fR , Rec.\ F.1, \(sc\ C8.
.LP
.rs
.sp 39P
.sp 2P
.LP
\fBMONTAGE:\fR Recommandation R.103 sur le reste de cette page.
.sp 1P
.RT
.LP
.bp