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.nr LL 40.5P
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.nr FM 6P
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.po 4P

.rs
\v | 5i'
.sp 1P
.ce 1000
\v'12P'
\s12PART\ II
\v'4P'
.RT
.ce 0
.sp 1P
.ce 1000
\fBRecommendations E.230 to E.277\fR \v'2P'
.EF '%	 \ \ \ ^''
.OF ''' \ \ \ ^	%'
.ce 0
.sp 1P
.ce 1000
\fBOPERATIONAL\ PROVISIONS\ RELATING\ TO\fR 
.ce 0
.ce 1000
\fBCHARGING\ AND\ ACCOUNTING\ IN\fR 
.ce 0
.sp 1P
.ce 1000
\fBTHE\ INTERNATIONAL\ TELEPHONE\ SERVICE\fR 
.ce 0
.sp 1P
.LP
.rs
.sp 28P
.LP
.bp
.LP
\fBMONTAGE:\fR PAGE 276 = PAGE BLANCHE
.sp 1P
.RT
.LP
.bp
.sp 1P
.ce 1000
\v'3P'
SECTION\ 1
.ce 0
.sp 1P
.ce 1000
\fBCHARGING\ (DETERMINATION\ OF\ COLLECTION\ CHARGES)\fR 
.ce 0
.sp 1P
.ce 1000
\fBIN\ THE\ INTERNATIONAL\ TELEPHONE\ SERVICE\fR \v'1P'
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.230\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBCHARGEABLE\ DURATION\ OF\ CALLS\fR \v'1P'
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.230''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.230	%'
.ce 0
.sp 1P
.PP
\fB1\fR International operators should allow no tolerance in their
assessment of the chargeable duration of calls.
.sp 1P
.RT
.PP
\fB2\fR 
Metering devices
controlled by operators should be rapid in action and have the utmost accuracy.
.sp 9p
.RT
.PP
\fB3\fR In the automatic service (and, in the case of station calls, in 
the manual and semiautomatic service) the chargeable duration should begin 
from 
the receipt of the 
answer signal from the called station
(see the
definitions
in Recommendation\ E.100), since the 
existence of an unchargeable call
period
, however short, might lead to misuse of the service for the
transmission of short messages without payment.
.sp 9p
.RT
.PP
The chargeable duration ends when the caller gives the
clear\(hyforward
signal
or, if the caller has not replaced the receiver, when the call is
cleared down by an operator in the performance of her duties in manual or
semiautomatic working, or as a result of a clearing signal from the called
party when an exchange clears the connection. In the latter case, the
chargeable duration ends with some slight delay following receipt of the
clearing signal from the called party
.
.PP
\fB4\fR 
It is unnecessary to inform the person making an international call of 
the exact moment at which the charging begins. 
.sp 9p
.RT
.PP
\fB5\fR 
An Administration should not give its operators instructions to advise 
subscribers of successive charging periods unless a prior agreement to 
this effect has been reached with the other Administrations. 
.sp 9p
.RT
.PP
\fB6\fR 
Nevertheless, if some Administrations consider it desirable to indicate 
to callers the expiry of each charging period, an automatic device, or 
one controlled by the operator at the originating international exchange, 
can be used for this purpose, on condition that this indication is regarded 
merely as an advice which is not binding on the Administration as regards 
charging.
.bp
.sp 9p
.RT
.sp 2P
.LP
\fBRecommendation\ E.231\fR 
.RT
.sp 2P
.ce 1000
\fBCHARGING\ IN\ AUTOMATIC\ SERVICE\ FOR\ CALLS\ TERMINATING\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.231''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.231	%'
.ce 0
.ce 1000
\fBON\ SPECIAL\ SERVICES\fRif\fB\ FOR\ SUSPENDED,\ CANCELLED\fR 
.ce 0
.sp 1P
.ce 1000
\fBOR\ TRANSFERRED\ SUBSCRIBERS\fR 
.ce 0
.sp 1P
.PP
It is desirable for calls terminating on special services for
suspended, cancelled or transferred subscribers
in the international
automatic service to receive the same treatment in different countries.
.sp 1P
.RT
.PP
The CCITT considers that no charge should be made for these
calls.
.PP
\fINote\fR \ \(em\ As far as all the 
signalling systems
involved in a
given connection for any of the possible relations allow the 
transmission   of the \*Qno\(hycharge\*U information
, the 
answer signal
should not be
withheld. Nevertheless such a situation will not exist on a worldwide basis 
for a long period to come. Therefore it is appropriate, for the time being, 
to 
suppress the sending of the answer signal on the international circuits for
calls towards these special services. It should also be noted that according 
to Recommendation\ Q.118, such calls will be cleared upon expiry of a certain 
fixed time\(hyout. 
\v'2P'
.RT
.LP
.sp 2P
.LP
\fBRecommendation\ E.232\fR 
.RT
.sp 2P
.ce 1000
\fBCHARGING\ FOR\ CALLS\ TO\ SUBSCRIBER'S\ STATION\ CONNECTED\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.232''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.232	%'
.ce 0
.ce 1000
\fBEITHER\ TO\ THE\ ABSENT\ SUBSCRIBER'S\ SERVICE\ OR\ TO\ A\fR 
.ce 0
.sp 1P
.ce 1000
\fBDEVICE\ SUBSTITUTING\ A\ SUBSCRIBER\ IN\ HIS\ ABSENCE\fR 
.ce 0
.sp 1P
.PP
\fB1\fR 
When a subscriber's line is connected to the absent
subscriber's service or to a device which answers the telephone in the
subscriber's absence (and may possibly record a message or exchange data) the
absent subscriber's service
or the device is assumed to be equivalent to a person answering for the 
subscriber at the latter's express wish. The call shall therefore be set 
up and charged in the normal manner. 
.sp 1P
.RT
.sp 1P
.LP
1.1
	\fIStation calls\fR 
.sp 9p
.RT
.PP
For station calls, charging takes effect on receipt of an
answer:
.RT
.LP
	\(em
	from the absent subscriber's service, or
.LP
	\(em
	from a device substituting a subscriber in his
absence.
.sp 1P
.LP
1.2
	\fIPersonal calls\fR 
.sp 9p
.RT
.PP
The caller is informed that the line is connected to the absent
subscriber's service or to a device substituting the called party in his
absence. If he accepts the call he is charged on the basis of duration 
and the special charge for a personal call is levied. If he does not accept 
the call, no charge is levied. 
.RT
.PP
\fB2\fR 
This Recommendation applies to manual, semiautomatic and
automatic services.
.sp 9p
.RT
.LP
.rs
.sp 4P
.LP
.bp
.sp 1P
.ce 1000
\v'3P'
SECTION\ 2
.ce 0
.sp 1P
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\fBPROCEDURES\ FOR\ REMUNERATION\ OF\ ADMINISTRATIONS\fR 
.ce 0
.sp 1P
.ce 1000
\fBFOR\ FACILITIES\ MADE\ AVAILABLE\fR \v'1P'
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.250\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBNEW\ SYSTEM\ FOR\ ACCOUNTING\ IN\ INTERNATIONAL\ TELEPHONY\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.250''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.250	%'
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.150.
\v'1P'
.sp 1P
.RT
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.251\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBOLD\ SYSTEM\ FOR\ ACCOUNTING\ IN\ INTERNATIONAL\ TELEPHONY\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.251''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.251	%'
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.151.
\v'1P'
.sp 1P
.RT
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.252\fR 
.RT
.sp 2P
.ce 1000
\fBMODE\ OF\ APPLICATION\ OF\ THE\ FLAT\(hyRATE\ PRICE\ PROCEDURE\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.252''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.252	%'
.ce 0
.ce 1000
\fBSET\ FORTH\ IN\ RECOMMENDATIONS\ D.67\ AND\ D.150\ FOR\ REMUNERATION\ OF\fR 
.ce 0
.sp 1P
.ce 1000
\fBFACILITIES\ MADE\ AVAILABLE\ TO\ THE\ ADMINISTRATIONS\ OF\ OTHER\ COUNTRIES\fR 
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.160.
.sp 1P
.RT
.ce 0
.sp 1P
.LP
.rs
.sp 9P
.LP
.bp
.LP
\fBMONTAGE\fR : \ 
PAGE 280 = PAGE BLANCHE
.sp 1P
.RT
.LP
.bp
.sp 1P
.ce 1000
\v'3P'
SECTION\ 3
.ce 0
.sp 1P
.ce 1000
\fBMEASURING\ AND\ RECORDING\ CALL\ DURATIONS\fR 
.ce 0
.sp 1P
.ce 1000
\fBFOR\ ACCOUNTING\ PURPOSES\fR 
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.260\fR 
.RT
.sp 2P
.ce 1000
\fBBASIC\ TECHNICAL\ PROBLEMS\ CONCERNING\ THE\fR \fB\ MEASUREMENT\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.260''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.260	%'
.ce 0
.sp 1P
.ce 1000
\fBAND\ RECORDING\ OF\ CALL\ DURATIONS\fR 
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBRecording call duration\fR 
.sp 1P
.RT
.PP
1.1
Technically 
\fIcall duration\fR is the interval that
elapses between:
.sp 9p
.RT
.LP
	\(em
	 the moment when the clear condition is detected at the point where the 
recording of the call duration takes place, and 
.LP
	\(em
	 the moment when the clear condition (clear forward signal) is detected 
at the same point. 
.PP
It follows that the apparatus used to record call duration of
automatic calls must be capable of detecting the two moments mentioned above
and of measuring the interval between them.
.PP
1.2
When an Administration using a simplified signalling system has recourse 
to recording holding times for the establishment of international 
accounts, it is necessary to have a conversion factor making it possible to
obtain the call duration from the 
holding time
. The determination of
this conversion factor requires fairly close observation. The 
ratio of
holding
time to call duration
may not be the same for all the circuits of a single group, so that a fairly 
large number of circuits must be observed in order to 
.sp 9p
.RT
.LP
find a reliable conversion factor. Moreover, the holding time also depends 
on the availability of switching equipment in the incoming country, as 
well as the reaction of subscribers when they hear ringing tone, busy tone, 
etc.; the 
holding time for a given call duration may thus be extremely
variable
.FS
In Recommendation\ D.150, \(sc\ 4.1.4\ [1] holding time is not
recommended because of the wide variations between chargeable time and
holding time in different relations and in different call types, which
makes the use of holding time inappropriate for remunerating
Administrations of countries of destination.
.FE
.
.LP
.sp 2P
.LP
\fB2\fR 	\fBDiscrimination between automatic and semiautomatic calls\fR 
.sp 1P
.RT
.PP
Since different accounting procedures are used for automatic and
semiautomatic calls, the recording apparatus must be capable of distinguishing 
between these two types of calls and must record the call duration of 
automatic calls only.
.PP
Discrimination can be effected by one of the following
methods:
.RT
.LP
	a)
	by connecting the measuring apparatus to a point in the
exchange through which only automatic traffic is routed;
.LP
	b)
	by recording call durations only for calls containing the
\fIdiscriminating\fR digit
\ 0 used in automatic working (see the
Recommendation\ Q.104 cited in\ [2]).
.PP
Method b) may be particularly useful when both automatic and
semiautomatic calls originate at exchanges within the national network 
and are routed to the outgoing international exchange over a common group 
of 
circuits.
.bp
.sp 2P
.LP
\fB3\fR 	\fBOmission of international transit traffic from the records\fR 
\fBof call duration\fR 
.sp 1P
.RT
.PP
All 
records of call duration
will be taken in the outgoing  country
and will relate to calls originating in that country. It will therefore be
necessary, in an international exchange which routes both terminal and
international transit traffic, to exclude the call duration of international
transit calls passing through the exchange.
.PP
It will be difficult to discriminate between originated calls and
transit calls on the outgoing international circuits and it may therefore be
necessary to segregate this traffic within the exchange and connect the
recording apparatus at a point in the exchange where transit traffic is not
encountered.
.RT
.sp 2P
.LP
\fB4\fR 	\fBDiscrimination according to destination\fR 
.sp 1P
.RT
.PP
4.1
The records of call durations obtained by the recording
apparatus
must be related to particular countries of destination and, if required, 
to the charging areas of the country of destination; the recording apparatus 
should 
therefore be capable of identifying the destination of a call and of
associating the measured call duration with this destination.
.sp 9p
.RT
.LP
.PP
\fINote\fR \ \(em\ For drawing up international accounts (apart from frontier 
relations) it is not necessary to know the origin of the call or the charging 
zone from which it comes. The differences in shares resulting from different 
outgoing charging zones in a given country are kept by that country.
.sp 1P
.LP
4.2
	\fIIncoming country constituting a single charging zone\fR 
.sp 9p
.RT
.PP
Where the recording apparatus is connected to a circuit group
carrying only terminal traffic, no discrimination is required. Where, however, 
a circuit group carries traffic to more than one country, discrimination 
between these countries must be effected from an examination of the
international code for the country and/or the type of seizing signal (terminal 
or transit) which is sent over the international circuits. 
.RT
.LP
.sp 1P
.LP
4.3
	\fIIncoming country consisting of several charging zones\fR 
.sp 9p
.RT
.PP
If the accounting procedure agreed between two countries demands
the production of separate records of call durations for calls made to each
charging zone in an incoming country, the recording apparatus must be arranged 
to discriminate between the calls to the different charging zones according 
to the first one or first two digits of the called station's national 
(significant) number
.FS
See the definition of the national (significant)
number in Recommendation\ E.160.
.FE
(see Recommendation\ E.163).
.RT
.LP
.sp 1P
.LP
4.4
	\fISpecial frontier arrangements\fR 
.sp 9p
.RT
.PP
To take account of the special system of 
charging for frontier
relations
(reduced charges between neighbouring frontier zones), special
steps will have to be taken to discriminate between automatic calls in 
frontier relations and other automatic calls. This discrimination will 
be made every 
time that frontier traffic is routed wholly or partly (overflow) by
long\(hydistance international circuits having devices for measuring call
duration.
.PP
This discrimination will in general necessitate:
.RT
.LP
	a)
	further 
analysis of the national (significant) number of
the called subscriber
than the one which is quoted in
Recommendation\ E.163, and
.LP
	b)
	the determination of the origin of the call, since
frontier charges
depend on the distance between the
outgoing and the incoming 
frontier zones
.
.LP
.sp 2P
.LP
\fB5\fR 	\fBDiscrimination according to route and destination\fR 
.sp 1P
.RT
.PP
In general there will be little difficulty in determining the route taken 
by a call on leaving the outgoing international exchange. If the 
recording apparatus is connected to the international circuits, then of 
course the recordings obtained will be appropriate to the route in question. 
If, 
however, the recording apparatus is connected to a point in the exchange 
remote from the outgoing circuits and the call to a particular country 
has the choice of more than one route, then information in respect of the 
actual route taken by the call must be supplied to the recording apparatus. 
.bp
.RT
.sp 2P
.LP
\fB6\fR \fBDistribution of traffic in an international exchange\fR \fBfor\fR 
\fBthe purpose of\fR \fBmeasuring call durations\fR 
.sp 1P
.RT
.PP
By way of example, Figure\ 1/E.260 is given hereafter showing how
traffic should be distributed in an international exchange so as to take
account of the provisions above.
.RT
.LP
.rs
.sp 40P
.ad r
\fBFigure 1/E.260 p. 342\fR 
.sp 1P
.RT
.ad b
.RT
.PP
The traffic passing through the international exchange is divided
into the following four groups, as shown on the figure:
.LP
	i)
	international transit traffic;
.LP
	ii)
	automatic traffic (originated locally);
.LP
	iii)
	semiautomatic traffic (originated locally);
.LP
	iv)
	combined automatic and semiautomatic traffic from provincial
exchanges.
.PP
These groups would employ independent groups of link circuits and
registers. Only group\ ii) and possibly group\ iv) would be involved in 
measuring call duration. 
.bp
.PP
The following auxiliary equipment is envisaged:
.RT
.LP
	a)
	for each link circuit in groups\ ii) and\ iv), a selecting
device capable of dealing with every possible combination of
route/country or \fIcharging zone\fR destination;
.LP
	b)
	for each link circuit in group\ iv), a device to take care of
the discrimination between semiautomatic and automatic traffic;
.LP
	c)
	for registers in groups\ ii) and\ iv), equipment for analyzing
country codes and if necessary an appropriate number of digits of
the national (significant) number of the called subscriber in
order to discriminate between charging zones (see
Recommendation\ E.163, \(sc\ 1.2);
.LP
	d)
	for registers in group\ iv), a device to recognize the
discriminating digit\ 0 used for automatic working;
.LP
	e)
	a means of recording the call duration for each combination
of route/country or charging zone destination.
.sp 2P
.LP
	\fBReferences\fR 
.sp 1P
.RT
.LP
[1]
	CCITT Recommendation \fINew system for accounting in international\fR 
\fItelephony\fR , Rec.\ D.150, \(sc\ 4.1.4.
.LP
[2]
	CCITT Recommendation \fILanguage digit or discrimination digit\fR ,
Rec.\ Q.104, \(sc\ 1.4.2.
.sp 2P
.LP
\fBRecommendation\ E.261\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBDEVICES\ FOR\ MEASURING\ AND\ RECORDING\ CALL\ DURATIONS\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.261''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.261	%'
.ce 0
.sp 1P
.PP
There are three main methods used for measuring call
duration:
.sp 1P
.RT
.sp 2P
.LP
\fB1\fR \fBUse of\fR \fBapparatus of the type which meters the quantity 
of\fR \fBelectricity\fR \fB(ampere\(hyhour meter or coulomb\(hymeter)\fR 
.sp 1P
.RT
.PP
This type of meter is permanently connected to the circuits or
equipment under observation; for the measurements in question, the current
strength in the meter is at all times proportional to the number of circuits 
or units of equipment in the speech position. With this type of apparatus 
the 
accuracy of the measurements depends on:
.RT
.LP
	a)
	 errors in the meter (shunt included) itself; in any case, in the absence 
of special arrangements, the accuracy of the latter 
.LP
is not so good for intensities which are only a small fraction of
the nominal intensity for which the apparatus is designed;
.LP
	b)
	the accuracy and possibly the variations with time of the
resistors inserted in the circuits to be observed;
.LP
	c)
	 the ohmic resistance of the connections between the measuring equipment 
and the circuits to be observed; 
.LP
	d)
	voltage variations in the supply battery used.
.PP
Obviously, the longer the period of observation, the greater are the chances 
that partial compensations will occur between the various causes of 
error. With such apparatus it seems unlikely that more than a 2%\ accuracy of
measurements can be obtained for measurements made over an adequate period 
of time which includes hours of varying load; measurements made only at 
times when there is very little traffic might involve a considerably greater 
error.
.sp 2P
.LP
\fB2\fR 	\fBUse of\fR \fBpulse\(hycounting meters\fR 
.sp 1P
.RT
.PP
With this method, the circuits or equipment under observation are
connected, for the duration of a call, to pulse\(hycounting meters which 
receive pulses from a common timing mechanism at suitable intervals, for 
example every six seconds. The call duration is deduced from the meter 
readings. 
.RT
.LP
.sp 2P
.LP
\fB3\fR 	\fBUse of a\fR \fBdevice for periodically scanning circuits or\fR 
\fBequipment\fR 
.sp 1P
.RT
.PP
These devices can be based on either the conventional type of
equipment (relays, crossbar switch, etc.) or some form of electronic
equipment.
.bp
.RT
.sp 2P
.LP
\fB4\fR 	\fBDegree of accuracy of methods\ 2 and 3\fR 
.sp 1P
.RT
.PP
With the two last\(hynamed methods, the degree of accuracy of
measurements depends on:
.RT
.LP
	\(em
	 the average call duration and the statistical distribution of call durations; 
.LP
	\(em
	the number of calls observed;
.LP
	\(em
	the interval between the sending of pulses (method\ 2) or the
scanning interval (method\ 3).
.PP
It is also possible to assess mathematically, as a function of these factors, 
the anticipated degree of accuracy. Errors may also arise from the 
operation of the meter in method\ 3, or from accidental variations in the
pulsing or scanning interval.
.PP
There is no doubt that if the number of calls observed is sufficiently 
high it is possible, using these methods and without reducing the pulse\(hysending 
interval or the scanning interval to such a small value that operation 
difficulties would arise with classic\(hytype apparatus, to obtain greater
accuracy than could be obtained with the method described in \(sc\ 1\ above.
.RT
.sp 2P
.LP
\fB5\fR 	\fBFault indication\fR 
.sp 1P
.RT
.PP
It is recommended that provision should be made for indicating faults in 
the measuring and recording device. There are two possibilities: 
.RT
.LP
	a)
	 to design the measuring and recording apparatus so that there is a permanent 
check on its operation, with an alarm system to 
indicate faults;
.LP
	b)
	to provide special equipment to make a routine check of the
operation of the measuring equipment.
.sp 2P
.LP
\fB6\fR 	\fBEquipment design\fR 
.sp 1P
.RT
.PP
The design of equipment for measuring and recording call durations is left 
to Administrations. Some information will be found in Annex\ A. 
\v'1P'
.RT
.LP
.ce 1000
ANNEX\ A
.ce 0
.sp 1P
.ce 1000
(to Recommendation E.261)
.sp 9p
.RT
.ce 0
.sp 1P
.ce 1000
\fBMeasuring call duration\fR 
.sp 1P
.RT
.ce 0
.PP
A.1
The technique to be adopted for recording call durations of
automatic traffic will depend on the accounting arrangements agreed between
Administrations and particularly on whether recordings are to be made:
.sp 1P
.RT
.LP
	\(em
	by country of destination alone;
.LP
	\(em
	by route and country of destination;
.LP
	\(em
	by route, country of destination and charging zone.
.PP
In all cases it will be necessary to discriminate between
automatic and semiautomatic traffic and possibly transit traffic.
.LP
.PP
A.2
Assuming that it is possible to identify automatic calls on the outgoing 
international circuit and that the circuits carry only terminal 
traffic, the measurement of call durations could be effected by connecting a
measuring and recording device to each international circuit. The disadvantage 
of this scheme is the large number of recorders to be provided and read 
daily.
.sp 9p
.RT
.PP
A single recorder could be made to serve a group of international circuits 
by arranging for the recorder to be connected to each circuit of a 
group in turn, say every six\ seconds, and for the recorder to operate 
each time that an international circuit in the answered condition is encountered. 
The 
recorder would then show the total call duration of the circuit
group.
.bp
.PP
A.3
Where transit routings are involved and the recordings are
required
on the basis of route and country of destination, separate totals of call
durations will be required for each country served by the route in question. 
In other words, it will be necessary to determine the destination of each 
call and record the call duration on the appropriate recorder. 
.sp 9p
.RT
.LP
.PP
This may be found to be a complicated process and it may be more
convenient to connect the recorder at a point remote from the international
circuit, for example at the register access relay set, where information in
respect of the destination and routing of the call can be obtained from the
outgoing international register. Figure\ A\(hy1/E.261 illustrates an arrangement 
in which 
the selector\ A is positioned under the control of the register to connect 
the appropriate route and destination recorder to the register access relay 
set. 
.PP
The recorder could be an ampere\(hyhour meter or it could consist of a
meter and a selector arranged to scan all the register access relay sets 
which have been connected to this particular route and destination recorder. 
.RT
.LP
.rs
.sp 16P
.ad r
\fBFigure A\(hy1/E.261 p. 343\fR 
.sp 1P
.RT
.ad b
.RT
.PP
A.4
A similar arrangement to Figure\ A\(hy1/E.261 can be employed where  recordings
are required on the basis of route, country of destination and charging 
zone. The additional complications introduced in determining the charging 
zone mainly concern the outgoing register but it should be noted that a 
greater number of separate call duration recorders will then be needed. 
.sp 9p
.RT
.LP
.PP
A.5
The number of recorders or separate records of call durations
is equal to the summation, for all destinations, of the product of number of
routes by number of charging zones for each country of destination. The
capacity of selector\ A in Figure\ A\(hy1/E.261 must be sufficient to permit 
access to any 
recorder and the economics of this scheme will be determined by the number 
of separate recordings required and the total volume of international traffic 
originated at the exchange concerned.
.sp 9p
.RT
.PP
A.6
For a large number of separate recordings, Administrations
might
consider whether it would be cheaper to use electronic methods for recording
call durations. In this connection Administrations might take into account 
the possible future introduction of cheap rates which could double the 
number of 
separate records required.
.sp 9p
.RT
.LP
.rs
.sp 5P
.LP
.bp
.sp 1P
.ce 1000
\v'3P'
SECTION\ 4
.ce 0
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\fBESTABLISHMENT\ AND\ EXCHANGE\ OF\ INTERNATIONAL\ ACCOUNTS\fR \v'1P'
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.270\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBMONTHLY\ TELEPHONE\ AND\ TELEX\ ACCOUNTS\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.270''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.270	%'
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.170.
\v'1P'
.sp 1P
.RT
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.275\fR 
.RT
.sp 2P
.ce 1000
\fBTRANSMISSION\ IN\ ENCODED\ FORM\ OF\ MONTHLY\ INTERNATIONAL\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.275''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.275	%'
.ce 0
.sp 1P
.ce 1000
\fBACCOUNTING\ INFORMATION\fR 
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.190.
\v'1P'
.sp 1P
.RT
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.276\fR 
.RT
.sp 2P
.ce 1000
\fBTRANSMISSION\ IN\ ENCODED\ FORM\ OF\ TELEPHONE\ REVERSED\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.276''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.276	%'
.ce 0
.sp 1P
.ce 1000
\fBCHARGE\ BILLING\ AND\ ACCOUNTING\ INFORMATION\fR 
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.176.
\v'1P'
.sp 1P
.RT
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.277\fR 
.RT
.sp 2P
.ce 1000
\fBCONVENTIONAL\ TRANSMISSION\ OF\ INFORMATION\ NECESSARY\ FOR\ THE\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.277''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.277	%'
.ce 0
.ce 1000
\fBCOLLECTION\ OF\ CHARGES\ AND\ THE\ ACCOUNTING\fR 
.ce 0
.sp 1P
.ce 1000
\fBREGARDING\ COLLECT\ AND\ CREDIT\ CARD\ CALLS\fR 
.ce 0
.sp 1P
.ce 1000
The complete text of this Recommendation is contained in
Recommendation\ D.174.
.sp 1P
.RT
.ce 0
.sp 1P
.LP
.bp
.LP
\fBMONTAGE\fR : \ 
PAGE 288 = PAGE BLANCHE
.sp 1P
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\s12PARTE\ III
\v'4P'
.RT
.ce 0
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\fBRecommendations\ E.300\ to\ E.323\fR \v'2P'
.EF '%	 \ \ \ ^''
.OF ''' \ \ \ ^	%'
.ce 0
.sp 1P
.ce 1000
\fBUTILIZATION\ OF\ THE\ INTERNATIONAL\fR 
.ce 0
.ce 1000
\fBTELEPHONE\ NETWORK\ FOR\fR 
.ce 0
.sp 1P
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\fBNON\(hyTELEPHONY\ APPLICATIONS\fR 
.ce 0
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.LP
.rs
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.LP
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.LP
\fBMONTAGE:\fR PAGE 290 = PAGE BLANCHE
.sp 1P
.RT
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\v'3P'
SECTION\ 1
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\fBGENERAL\fR \v'1P'
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.300\fR 
.RT
.sp 2P
.ce 1000
\fBSPECIAL\ USES\ OF\ CIRCUITS\ NORMALLY\ EMPLOYED\ FOR\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.300''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.300	%'
.ce 0
.sp 1P
.ce 1000
\fBAUTOMATIC\ TELEPHONE\ TRAFFIC\fR 
.ce 0
.sp 1P
.LP
	The\ CCITT
.sp 1P
.RT
.sp 1P
.LP
\fIconsidering\fR 
.sp 9p
.RT
.PP
(a)
that special services exist which occasionally require the provision of 
telephone circuits for uses such as: 
.LP
	\(em
	reserve circuits for VF telegraphy
,
.LP
	\(em
	circuits for phototelegraph transmissions
,
.LP
	\(em
	control circuits for programme transmissions
,
.LP
	\(em
	leased circuits (other than permanent full\(hytime
leases);
.PP
(b)
that the international telephone service is becoming more and more automatic, 
and that only a few manual circuits will be kept to form a reserve network; 
.PP
(c)
that it is therefore necessary to provide 
automatic
circuits for special uses
other than telephony;
.PP
(d)
that 
telephone circuits assigned for special uses
must, when needed, be made available to the special services as
rapidly as possible;
.PP
(e)
that it must be guaranteed that, after the circuits have
been used for a special purpose, they will be returned to the
telephone service without delay;
.PP
(f
)
that the switching of circuits for special purposes should not disturb 
the operation of telephone service. 
.sp 1P
.LP
\fIrecommends\fR 
.sp 9p
.RT
.PP
that the following provisions be observed:
.PP
\fB1\fR 
In an international telephone relation, the number of automatic circuits 
assigned for special purposes should be in reasonable proportion to 
the total number of circuits, so that their occupation will not hamper 
the flow of automatic telephone traffic. 
.sp 9p
.RT
.PP
\fB2\fR 
Circuits to be used for special purposes should be passed at the outgoing 
and incoming ends through 
transfer panels
on which the wanted circuit is disconnected manually from the telephone 
equipment and connected to the terminal of the special service concerned. 
.bp
.sp 9p
.RT
.PP
Alternatively, circuits assigned for special uses should be fitted, in 
the telephone equipment, with a device for automatic switching to the 
transfer panel of the special service, the operation being commanded by the
latter. (This method is preferable because with the first method a telephone
call could be interrupted if proper care is not exercised.)
.PP
\fB3\fR 
The switching operations should take place under the control of the outgoing 
international maintenance centre (IMC). The IMC may delay or 
limit the provision of telephone circuits for other purposes, particularly 
when restrictions are imposed on the telephone traffic. 
.sp 9p
.RT
.LP
.PP
\fB4\fR 
The following arrangements should be followed when special
connections are set up and cleared:
.sp 9p
.RT
.LP
	a)
	 The occupation of a telephone circuit for a special purpose should be 
marked on the transfer panel at the outgoing end; 
conversely, if such a circuit is in fact engaged, it must be
marked busy in the telephone switching equipment.
.LP
	b)
	 A circuit assigned to a special use may not be taken for the service 
in question if a telephone call is in progress. However, 
arrangements should be made to ensure that the circuit cannot be
engaged by another telephone call when the call is over
\fI(preliminary blocking)\fR .
.LP
	c)
	The circuits in a group of telephone circuits that are
reserved for special uses should be last\(hychoice circuits, to
reduce the risk of finding them busy when required.
.LP
	d)
	When a circuit is free, the supervisor in charge of the
transfer panel at the outgoing end takes the necessary steps
to withdraw the circuit from the telephone service. The
responsible supervisor at the incoming end is then asked to make
the necessary operations if the telephone equipment is not
disconnectable by remote control.
.LP
	e)
	While awaiting notification from the incoming end of
completion of transfer to the special service, the outgoing
supervisor tests the connection before making it available
for its new functions.
.LP
	f
)
	The same procedure is followed at the outgoing end
when the circuit is restored to the telephone service. To prevent a
subsequent telephone call from being ineffective, care must be
taken to clear the special call at the incoming end first.
.PP
\fB5\fR 
Bookings of leased circuits or order lines for programme
transmissions are arranged in advance and are not urgent. The delays required 
by the connection of two circuits in tandem when a connection is operated 
entirely in automatic transit give rise to no particular difficulties.
.sp 9p
.RT
.PP
\fB6\fR 
Where telegraph systems are concerned, the primary requirement is rapid 
replacement of the faulty VF bearer circuit. In view of the delay 
which would occur in employing two separate links to form a reserve circuit, 
it appears that in relations in which automatic transit switching is the 
normal 
method of operation, a direct circuit should be retained.
.sp 9p
.RT
.LP
.PP
Such a direct circuit could be manual or automatic. An automatic
circuit would normally be used to carry the telephone traffic. It should be
noted that this will then be used as a first\(hychoice route and will thus 
carry the heaviest load. The risk of finding it busy, when needed, will 
therefore be at its maximum. 
.PP
In such circumstances, preliminary blocking of the wanted circuit
should be effected (see \(sc\ 4b)\ above). As long as the equipment is 
unable to 
perform this operation it will be preferable to keep one manual direct
circuit.
.RT
.PP
\fB7\fR 
The delay in establishing phototelegraph calls via an
international phototelegraph position transit centre
(transit IPP) is not so critical. In this case, application of Recommendation\ 
E.320 will speed up the placing of two circuits end to end at the transit 
centre to establish 
the connection, and it will not be necessary to keep direct circuits in
relations where automatic switching is the method normally used for telephone 
calls in transit. 
.sp 9p
.RT
.PP
\fB8\fR 
The same circuit should not be assigned to more than one special service, 
so that the various transfer panels for such services may be placed 
separate from one another should the terminal country so wish.
.sp 9p
.RT
.LP
.bp
.sp 2P
.LP
\fBRecommendation\ E.301\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBIMPACT\ OF\ NON\(hyVOICE\ APPLICATIONS\ ON\ THE\ TELEPHONE\ NETWORK\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.301''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.301	%'
.ce 0
.sp 1P
.LP
\fB1\fR 	\fBIntroduction\fR 
.sp 1P
.RT
.PP
The present telephone network is capable of providing a bearer
service for a range of non\(hyvoice service applications. These include:
.RT
.LP
	\(em
	data (analogue coded),
.LP
	\(em
	facsimile,
.LP
	\(em
	phototelegraphy,
.LP
	\(em
	VF telegraphy.
.LP
.PP
VF telegraphy is not carried on the public switched telephone
network\ (PSTN). Furthermore, phototelegraphy calls use telephone circuits
removed from normal service, as set out in Recommendation\ E.320. For calls 
on the PSTN therefore, only data and facsimile services are considered 
below. 
.PP
Special considerations may need to be given to the suitability of the telephone 
network to carry these services because of their particular 
characteristics which differ from those of voice traffic in the following
ways:
.RT
.LP
	a)
	the transmission of these services is characterized by a
continuous power loading, compared to the syllabic bursts found in
speech;
.LP
	b)
	non\(hyvoice traffic often has a 24\(hyhour traffic profile different
from voice traffic, but similar to other non\(hyvoice services such
as telex;
.LP
	c)
	call holding times are often significantly shorter than
voice traffic.
.LP
.PP
While ISDN will be based on the concepts developed for the
telephone
network and may evolve by progressively incorporating additional functions 
and network features, the transition from existing networks to comprehensive 
ISDNs may require a period of time. On the understanding that non\(hyvoice 
application on the present telephone network demonstrates the provision 
of pre\(hyISDN bearer services, this Recommendation provides an analysis 
of some of the problems 
which may be encountered in the existing telephone network during the PSTN 
to ISDN transition period and suggests a number of solutions for these 
problems. 
.sp 2P
.LP
\fB2\fR 	\fBSignalling and transmission considerations\fR 
.sp 1P
.RT
.sp 1P
.LP
2.1
	\fISignalling\fR 
.sp 9p
.RT
.PP
Non\(hyvoice service signals can interfere with telephone circuit
signalling systems and vice versa.
.PP
Data or facsimile signals can interfere with signalling systems which use 
in\(hyband line signalling such as Signalling Systems No.\ 4, No.\ 5 and\ 
R1. 
Thus such non\(hyvoice calls should use the standardized systems set out in the
Series\ V and\ T Recommendations since these are designed to prevent interference 
with the standard signalling systems, either by avoiding the particular 
signalling frequencies or by
operating the guard circuit of the signalling receiver.
.PP
Despite the safeguards mentioned above, it may sometimes happen that the 
signalling receiver is momentarily operated by the carried service signal. 
In this case the splitting device in the signalling receiver will operate 
and cause a short discontinuity in the received service signal. 
.RT
.sp 2P
.LP
2.2
	\fITransmission\fR 
.sp 1P
.RT
.sp 1P
.LP
2.2.1
	\fIInterference to transmission systems\fR 
.sp 9p
.RT
.PP
If the proportion of non\(hyvoice calls is large, it can increase the overall 
power loading in a transmission assembly (group or supergroup). This 
can cause distortion in the group of signals and/or the operation of power
limiters which can adversely affect other calls or services in the same
transmission assembly.
.bp
.PP
In order to economize on the provision of international voice
channels, some international transmission systems may be fitted 
with speech interpolation systems
, such as TASI (time assignments speech
interpolation). Circuit gains are realized
by exploiting the silent period normally existing during speech conversations. 
Continuous 
non\(hyvoice service signals will cause the continuous operation of the speech
detectors and give rise to permanent association of the telephone circuit 
.PP
to the transmission channel. This in turn increases the probability of
noticeable speech clipping and in severe cases the occurrence of freeze\(hyout
where no channel is available. Thus the quality of speech on parallel voice
calls can be affected, resulting in a need to reduce the gain advantage 
of the speech interpolation system. 
.PP
Information on speech interpolation systems can be found in Supplement 
No.\ 2 of Fascicle\ VI.1. 
.RT
.sp 1P
.LP
2.2.2
	\fIInterference by transmission systems\fR 
.sp 9p
.RT
.PP
It may be the case that ordinary speech channels do not provide an adequate 
transmission path for some types of non\(hyvoice service, resulting in 
an unacceptable error performance, or in the worst case not allowing any 
service at all. 
.PP
Echo suppressors will not allow the transmission of duplex data unless 
the tone\(hydisabling signal is first applied and immediately followed 
by the 
service signal.
.PP
Some types of transmission systems do not support higher speed data
transmission. In particular, adaptive differential pulse code
.PP
modulation\ (ADPCM) specified in Recommendation\ G.721 uses a 32\ kbit/s 
coding technique for the speech channel and may not support higher data 
speeds, 
e.g.\ 9600\ bit/s.
.RT
.sp 1P
.LP
2.3
	\fIPotential solutions\fR 
.sp 9p
.RT
.PP
If the transmission of 
non\(hyvoice services
on the telephone network is found to cause problems due to the above issue, 
the Administrations concerned should take the following actions: 
.RT
.PP
2.3.1
It should be established for each bilateral relationship what
commercial and regulatory arrangements exist which recognize the need to
provide for non\(hyvoice services within prescribed quality of service
parameters.
.PP
2.3.2
If it is decided by the Administrations concerned that certain
services must be supported, then two approaches can be taken:
.LP
	a)
	only transmission systems allowing reliable performance
for non\(hyvoice services are used;
.LP
	b)
	separate routings are established for the whole or part
of the networks, where unreliable transmission would otherwise
occur.
.LP
.PP
2.3.3
In case b) above, it is necessary to know when subscribers are
initiating non\(hyvoice calls. There are three methods for achieving this:
.LP
	i)
	the subscriber line is known to be one originating
only non\(hyvoice calls, e.g.\ it is a facsimile terminal;
.LP
	ii)
	the subscriber sends some form of service indication to
the network, identifying a non\(hyvoice call request
(e.g.\ Recommendation\ E.131);
.LP
	iii)
	the subscriber dials or selects a particular prefix
before the international (or national) number requesting a
non\(hyvoice service call.
.PP
If these indications are directly available at the exchange where the separate 
routing is selected, then path selection need only combine this 
indication with the dialled digits. In other cases it is necessary for a
suitable signalling system to be employed to carry this indication forward 
to the special selection point. This may be done using signalling systems 
including special call categories. In particular, a call category \*Qdata 
call\*U is provided in Signalling Systems\ R2, No.\ 6 and No.\ 7, also 
No.\ 5 by 
.LP
bilateral agreement. The separate routing may be continued throughout the
network using either \*Qpath of entry\*U indications at the exchanges concerned 
or the special call category signals within the signalling system. Such 
special 
arrangements for non\(hyvoice calls may have an impact on charging
rates.
.bp
.sp 2P
.LP
\fB3\fR 	\fBTraffic profiles\fR 
.sp 1P
.RT
.PP
On international routes the peaks of voice and non\(hyvoice traffic
may occur at different times due to, for example, different time zones. Some
typical traffic profiles are described in Annex\ A. This difference has
implications when calculating the gain of speech interpolation systems 
such as TASI and DSI (digital speech interpolation). The gain is basically 
the ratio of the number of telephone circuits, 8those connected with the 
telephone switching system), to the number of bearer circuits (those connected 
to the transmission facilities). 
.PP
The number of required telephone circuits is designed to meet the
busy\(hyhour traffic volume, and the number of required bearer circuits is
calculated from the total number of circuits required for voice and non\(hyvoice 
traffic. As a result, there is a possibility that the peak time of required 
telephone circuits and bearer circuits may appear at different hours.
.PP
Therefore the number of required telephone circuits with speech
interpolation systems and bearer circuits needs to be dimensioned considering 
the 24\(hyhour traffic profiles of both voice and non\(hyvoice. 
.RT
.sp 2P
.LP
\fB4\fR 	\fBSpecial provisions for 
\fBend\(hyto\(hyend digital connectivity\fR 
.sp 1P
.RT
.PP
4.1
Within IDNs it is possible to transport data on an end\(hyto\(hyend basis 
using the digital bit stream rather than analogue modulated signals. When 
ISDN
features are implemented, the requirements of both voice and
non\(hyvoice
services will be met. Interim arrangements may exist before the ISDN however, 
that allow the provision of end\(hyto\(hyend digital connectivity for transmission 
of digital data.
.sp 9p
.RT
.PP
Compared to the call set\(hyup principles for voice calls, the
following arrangements need to be applied:
.LP
	i)
	only compatible digital circuits must be selected, e.g.\ all
circuits use transparent 64\ kbit/s transmission;
.LP
	ii)
	all digital speech processing (DSI) systems (e.g., CME,
DSI, ADPCM) must be disabled or bypassed in the data transmission phase;
.LP
	iii)
	any \(*m\(hylaw to A\(hylaw convertors must be disabled or
bypassed in the data transmission phase;
.LP
	iv)
	all echo suppressors or cancellors must be disabled or
bypassed in the data transmission phase;
.LP
	v)
	digital transmission attenuation pads must not be
used;
.LP
	vi)
	network and access signalling may be either in\(hyband
or out\(hyof\(hyband;
.LP
	vii)
	Recommendation\ E.164 numbering
plan
.FS
Recommendation E.164 encompasses E.163.
.FE
applies.
.PP
4.2
Details for these arrangements are for further study. In order
that these arrangements may be provided from the originating network to the
destination network, the signalling system applied should have the capability 
to convey such non\(hyvoice service requests; for example, in the case 
of TUP of the Signalling System No.\ 7, at least such as additional function 
must be 
implemented among Administrations concerned in order to convey the customer
request
for \*Qunrestricted bearer capability\*U to the transit and destination 
networks. It should be also noted that terminal compatibility cannot be 
negotiated 
between the originating terminal and destination terminal within the 
.LP
capability of TUP. In this case, therefore, the subscriber can only communicate 
with the destination number which, he knows in advance, is accommodating 
a 
compatible non\(hyvoice terminal.
.LP
.sp 2
.bp
.ce 1000
ANNEX\ A
.ce 0
.ce 1000
(to Recommendation E.301)
.sp 9p
.RT
.ce 0
.ce 1000
\fBTeletraffic characteristics of non\(hyvoice traffic\fR 
.sp 1P
.RT
.ce 0
.LP
A.1
	\fIMean call duration\fR 
.sp 1P
.RT
.PP
There can be a significant difference in call duration between
voice and non\(hyvoice traffic. For example, the mean call duration of 
non\(hyvoice traffic is three minutes in most cases, while the average 
call holding time for voice traffic can range between\ 6\(hy9\ minutes. 
.RT
.sp 1P
.LP
A.2
	\fI24\(hyhour traffic profile\fR 
.sp 9p
.RT
.PP
The 24\(hyhour non\(hyvoice traffic profiles measured are in general
alignment with business activities. The traffic peak appears at the end of
office hours in the originating country, which is similar to the profiles of
telex and record\(hytype telecommunication services in non\(hyattended mode of 
.PP
operation. The calculated profiles according to the hour(s) of time difference 
(i.e.,\ R\ =\ 0, 1, 2, |  |  | , 12) are shown in Figure\ A\(hy1/E.301, 
together with the examples of measured 24\(hyhour profile of the mixed 
voice and non\(hyvoice traffic in Figure\ A\(hy2/E.301. In cases where 
the countries have a significant 
time   difference
, the both\(hyway traffic (sum of outgoing and incoming traffic) has two 
traffic peaks, corresponding to the end of the business hours in each 
country.
.PP
Voice communication is only possible when calling and called parties are 
present at both ends and therefore, generally align with the schedule of 
human activities. Thus, peak hours of voice and non\(hyvoice traffic may 
differ. In Figure\ A\(hy2/E.301, countries\ A and\ B have similar peak 
hours for both traffic streams while country\ C has two peaks, one (earlier) 
for voice and the other 
for non\(hyvoice. This can contribute to flattening the traffic profile thus
making more efficient use of the circuit group. It should also be noted that
non\(hyvoice traffic may sharpen the peak of the profile in case of short
overlapping of business hours between two countries. This may affect the
dimensioning of the network and require additional circuits to cover only a
short period of time.
.PP
It is therefore important that countries measure and understand the
traffic on their routes so that efficient dimensioning of the network can be
undertaken.
.RT
.LP
.rs
.sp 23P
.ad r
\fBFigure A\(hy1/E.301, p. 3 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure A\(hy2/E.301, p. 4\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
\fBMONTAGE: PAGE 298 = BLANCHE\fR 
.sp 1P
.RT
.LP
.bp
.sp 1P
.ce 1000
\v'3P'
SECTION\ 2
.ce 0
.sp 1P
.ce 1000
\fBPHOTOTELEGRAPHY\fR 
.ce 0
.sp 1P
.sp 2P
.LP
\fBRecommendation\ E.320\fR 
.RT
.sp 2P
.ce 1000
\fBSPEEDING\ UP\ THE\ \fR \fBESTABLISHMENT\ AND\ CLEARING\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.320''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.320	%'
.ce 0
.sp 1P
.ce 1000
\fBOF\ PHOTOTELEGRAPH\ CALLS\fR 
.ce 0
.sp 1P
.PP
When international phototelegraph calls are sent over telephone circuits, 
the total time of occupation of the circuit often greatly exceeds the duration 
of the phototelegraph call itself. 
.sp 1P
.RT
.PP
It is also important that telephone circuits should be held for as short 
a time as possible. 
.PP
The CCITT therefore recommends to Administrations to bear the following 
directives in mind whenever it is technically practicable: 
.RT
.PP
\fB1\fR 
Telephone circuits intended for phototelegraph transmissions
should, at terminal repeater stations, pass through panels at the
international phototelegraph position (IPP) enabling these circuits to be
disconnected from the telephone service equipment and interconnected or
connected to 
phototelegraph stations
. Before switching on this circuit, it must be ensured that no telephone 
calls are in progress 
.FS
At the time
agreed upon with the telephone service, if such a previous agreement is
considered to be necessary by the telephone operating services.
.FE
. If there are calls, the circuit must be blocked as soon as the telephone 
call is over 
\fI(preliminary blocking)\fR .
.sp 9p
.RT
.PP
\fB2\fR 
The calling phototelegraph position must be ready to call the
corresponding phototelegraph position over the telephone circuit as soon 
as it notes that the chosen circuit has been cleared. The calling signal 
should 
automatically disconnect the telephone equipment from the circuit at the 
called end. The circuit is thus immediately available for the establishment 
of a 
phototelegraph call
.
.sp 9p
.RT
.LP
.PP
\fB3\fR 
If the called phototelegraph position has to be obtained through a transit 
phototelegraph position, the procedure outlined above is applied 
successively to the two circuits which are to be interconnected.
.sp 9p
.RT
.PP
\fB4\fR 
The same signal (see \(sc\ 2 above) can also be used to invite the incoming, 
and possibly the transit, IPP to enter the line: 
.sp 9p
.RT
.LP
	\(em
	if there are difficulties, or
.LP
	\(em
	to signal the end of transmission.
.PP
\fINote\fR \ \(em\ The calling frequency \fIf\fR\d2\uused for phototelegraphy
should be different from that used for telephone signalling \fIf\fR\d1\u. 
In the case of automatic or semiautomatic telephone circuits, frequency 
500/20\ Hz will be adopted as the signalling \fIf\fR\d2\ufrequency for
phototelegraphy.
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\fBRecommendation\ E.323\fR 
.RT
.sp 2P
.ce 1000
\fBRULES\ FOR\ PHOTOTELEGRAPH\ COMMUNICATIONS\ SET\ UP\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.323''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.323	%'
.ce 0
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\fBOVER\ CIRCUITS\ NORMALLY\ USED\ FOR\ TELEPHONE\ TRAFFIC\fR 
.ce 0
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.ce 1000
The complete text of this Recommendation is contained in
Recommendation F.82.
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.rs
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\v'12P'
\s12PART\ IV
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\fBRecommendations E.330 to E.333\fR \v'2P'
.EF '%	 \ \ \ ^''
.OF ''' \ \ \ ^	%'
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\fBISDN\ PROVISIONS\ CONCERNING\ USERS\fR 
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.rs
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\fBMONTAGE: PAGE 302 = PAGE BLANCHE\fR 
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\fBRecommendation\ E.330\fR 
.RT
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.ce 1000
\fBUSER\ CONTROL\ OF\ ISDN\(hySUPPORTED\ SERVICES\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.330''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.330	%'
.ce 0
.sp 1P
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	\fBIntroduction\fR 
.sp 1P
.RT
.PP
\fB1\fR 
This Recommendation describes the general aspects of user
control of ISDN\(hysupported services. In particular, access to the services 
and 
handling of communication sessions
are treated.
.sp 1P
.RT
.PP
A service is defined as in Recommendation I.112, \(sc 2.2.
.PP
A 
communication session
is a session between two or more
telecommunication parties in which unidirectional or bidirectional
communication takes place. This Recommendation primarily concerns sessions
where one or more people are involved.
.RT
.PP
\fB2\fR 
This Recommendation does not describe how to proceed in the services themselves; 
in fact, this Recommendation has been set up to be as 
service\(hyindependent as possible.
.sp 9p
.RT
.PP
\fB2\fR 
In stating and recommending user procedures it is important to have global 
information about terminal capabilities. This Recommendation, 
however, is drafted as terminal\(hyindependent as possible. It contains
fundamental principles of user interfaces as far as these are relevant 
to user access to the ISDN, and does not specify terminal requirements. 
.sp 9p
.RT
.sp 2P
.LP
	The\ CCITT,
.sp 1P
.RT
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.LP
\fIconsidering\fR 
.sp 9p
.RT
.PP
(a)
that the ISDN will make available new services for
customers and Administrations;
.PP
(b)
that the changeover from the present networks to the
ISDN will be gradual;
.PP
(c)
that, from a user's point of view, private networks and public networks 
offer some similar services and also services that one or the other does 
not provide; 
.PP
(d)
that certain services have specific user procedures and their own methods 
of presenting information to the user; 
.PP
(e)
that users may benefit from uniformity in user
procedures for selecting a service and for starting, switching between, and
ending communications;
.PP
(f)
that information from the telecommunication system to
the user can be sent in the form of tones, verbal announcements, or visual
indications on a display;
.PP
(g)
that the use of terminals containing a visual display is becoming more 
and more common in telecommunication applications; 
.PP
(h)
that the ISDN offer users the possibility of handling
two or more connections simultaneously;
.PP
(i)
that handling connections simultaneously may be
difficult for the user;
.PP
(j)
that information presentation to the user should be
based on human factors considerations;
.PP
(k)
that terminals may be distinguishable into dedicated
(service\(hyspecific) terminals and terminals with which several teleservices 
can be offered, 
.sp 1P
.LP
\fIrecommends\fR 
.sp 9p
.RT
.PP
(1)
that the methods with which communication sessions are selected, started, 
switched between each other and ended, should, where 
appropriate, make allowance for different levels of user experience;
.PP
(2)
that, when a similar capability using similar terminals is offered through 
a private network and a public network, user procedures 
should be similar;
.bp
.PP
(3)
that, where a terminal supports \*Qhigher
level\*U
.FS
\*QHigher level\*U and \*Qlower level\*U refer here to the degree to which 
the capabilities of a terminal facilitate its use. For example, a terminal 
with only digits and a star and a square (see Recommendation\ E.161) may 
be able to achieve the same functions through lower\(hylevel procedures 
as a better equipped terminal with, for example, dedicated function buttons, 
in addition to its 
dial, where higher\(hylevel, more convenient procedures could be used.
.FE
procedures and has the same function keys used for lower\(hylevel procedures in
other terminals, then these lower\(hylevel procedures should still be operable, 
to achieve the functionality reached by higher\(hylevel procedures. 
.PP
(4)
that, on more advanced telecommunication terminals,
however, other input mechanisms, having similar functions to those controlled 
by the function keys mentioned in\ (3), may replace these function keys; 
.PP
(5)
that, for voice and non\(hyvoice services, procedures
should be similar for analogous supplementary services when terminals with
similar capabilities are used;
.PP
(6)
that tones, verbal announcements and visual indications, which are used 
in the existing networks should not be changed in the ISDN as 
long as their functions remain the same;
.FS
See Recommendation\ E.184.
.FE
.
.PP
(7)
that ending a communication session can be accomplished from either end, 
except for emergency services; 
.PP
(8)
that it is preferred to give information to users at
either end of a communication path by means of an auditory or visual indication 
when the communication is on hold; 
.FS
Further study is required to determine whether or not a communication session 
which was put on hold becomes active as soon as the present communication 
session is ended by the user and, if so, 
whether this is the communication session which was put on hold first or 
last. This subject should also be dealt with in the next study period. 
.FE
.PP
(9)
that in those cases where starting or switching between communication sessions 
is not possible or may result in a deterioration of the existing communication 
session(s), appropriate auditory or visual indication 
should be given to the user;
.PP
(10)
that when two or more communication sessions are handled at the same time 
on the same telecommunication terminal and the user uses a 
stop procedure valid for all communication sessions, it is preferred to give
the user the opportunity to select which session or sessions are to be
terminated.
.sp 2P
.LP
\fBRecommendation\ E.333\fR 
.RT
.sp 2P
.sp 1P
.ce 1000
\fBMAN\(hyMACHINE\ INTERFACE\fR 
.EF '%	Fascicle\ II.2\ \(em\ Rec.\ E.333''
.OF '''Fascicle\ II.2\ \(em\ Rec.\ E.333	%'
.ce 0
.sp 1P
.PP
The text of this Recommendation is contained in
Recommendation\ Z.323. Recommendation\ Z.323, \(sc\ 2.5, 
\fIUser guidance\fR ,
contains useful information on help and guidance applicable to the more 
complex kind of service that may be mediated by an ISDN. 
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.RT
.LP
.sp 9
.bp