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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 2P
.LP
\fB4\fR 	\fBGeneral message format and information elements coding\fR 
.sp 1P
.RT
.PP
The figures and text in this section describe message contents.
Within each octet, the bit designated \*Qbit\ 1\*U is transmitted first, 
followed by bits\ 2, 3, 4,\ etc. Similarly, the octet shown at the top 
of each figure is sent first. 
.RT
.sp 1P
.LP
4.1
	\fIOverview\fR 
.sp 9p
.RT
.PP
Within this protocol, every message shall consist of the following  parts:
.RT
.LP
	a)
	protocol discriminator;
.LP
	b)
	call reference;
.LP
	c)
	message type;
.LP
	d)
	other information elements, as required.
.PP
Information elements a), b) and c) are common to all the messages and shall 
always be present, while information element\ d) is specific to each message 
type. 
.PP
This organization is illustrated in the example shown in
Figure\ 4\(hy1/Q.931.
.RT
.LP
.rs
.sp 16P
.ad r
\fBFigure 4\(hy1/Q.931 [T54.931], p.\fR 
.sp 1P
.RT
.ad b
.RT
.PP
A particular message may contain more information than a
particular (user or network) equipment needs or can understand. All equipment 
should be able to ignore any extra information, present in a message, which 
is not required for the proper operation of that equipment. For example, 
a user 
may ignore the calling party number if that number is of no interest to the
user when a SETUP message is received.
.PP
Unless specified otherwise, a particular information element may be
present only once in a given message.
.PP
The term \*Qdefault\*U implies that the value defined should be used in
the absence of any assignment, or the negotiation of alternative values.
.PP
When a field, such as the call reference value, extends over more
than
one octet, the order of bit values progressively decreases as the octet 
number increases. The least significant bit of the field is represented 
by the 
lowest numbered bit of the highest\(hynumbered octet of the field.
.RT
.sp 1P
.LP
4.2
	\fIProtocol discriminator\fR 
.sp 9p
.RT
.PP
The purpose of the protocol discriminator is to distinguish
messages for user\(hynetwork call control from other messages (to be defined)
within this Recommendation. It also distinguishes messages of this
Recommendation from those OSI network layer protocol units which are coded 
to other CCITT Recommendations and other standards. 
.bp
.PP
\fINote\fR \ \(em\ A protocol discriminator field is also included in the
user\(hyuser information element to indicate the user protocol within the user
information; however, the coding of the protocol discrimination in this 
case is shown in\ \(sc\ 4.5.29. 
.PP
The protocol discriminator is the first part of every message. The
protocol discriminator is coded according to Table\ 4\(hy1/Q.931.
.RT
.LP
.rs
.sp 12P
.ad r
\fBFigure 4\(hy2/Q.931 [T55.931], p.\fR 
.sp 1P
.RT
.ad b
.RT
.ce
\fBH.T. [T56.931]\fR 
.ce
TABLE\ 4\(hy1/Q.931
.ce
\fBProtocol discriminator\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(228p) .
.TE
.nr PS 9
.RT
.ad r
ter
\fBTable 4\(hy1/Q.931 [T56.931], p.\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
4.3
	\fICall reference\fR 
.sp 9p
.RT
.PP
The purpose of the call reference is to identify the call or
facility registration/cancellation request at the local user\(hynetwork 
interface to which the particular message applies. The call reference does 
not have 
end\(hyto\(hyend significance across ISDNs.
.PP
The call reference is the second part of every message. The call
reference is coded as shown in Figure\ 4\(hy3/Q.931. The length of the call
reference value is indicated in octet\ 1, bits\ 1\(hy4. The default maximum 
length of the call reference information element is three octets long. 
The actions 
taken by the receiver are based on the numerical value of the call reference
and are independent of the length of the call reference information element.
.PP
At a minimum, all networks and users must be able to support a call
reference value of one octet for a basic user\(hynetwork interface, and a call
reference value of two octets for a primary rate interface.
.PP
As a network option for a primary rate interface, the call reference value 
may be one octet also. In this case, a call reference value up to\ 127 
may be sent in one or two octets. 
.RT
.PP
The call reference information element includes the call reference value 
and the call reference flag. 
.PP
Call reference values are assigned by the originating side of the
interface for a call. These values are unique to the originating side only
within a particular D\(hyChannel layer two logical link connection. The call
reference value is assigned at the beginning of a call and remains fixed for
the lifetime of a call (except in the case of call suspension). After a call
ends, or, after a successful suspension, the associated call reference value
may be reassigned to a later call. Two identical call reference values 
on the same D\(hyChannel layer two logical link connection may be used 
when each value 
pertains to a call originated at opposite ends of the link.
.PP
The call reference flag can take the values \*Q0\*U or \*Q1\*U. The call
reference flag is used to identify which end of the layer two logical link
originated a call reference. The origination side always sets the call
reference flag to \*Q0\*U. The destination side always sets the call reference 
flag to a\ \*Q1\*U. 
.PP
Hence the call reference flag identifies who allocated the call
reference value for this call and the only purpose of the call reference
flag is to resolve simultaneous attempts to allocate the same call
reference value.
.PP
\fINote\ 1\fR \ \(em\ The call reference information element containing a dummy
call reference is one octet long and is coded \*Q0000\ 0000\*U. The use 
of the dummy call reference is specified in Recommendation\ Q.932. 
.PP
\fINote\ 2\fR \ \(em\ The numerical value of the global call reference is zero.
The equipment receiving a message containing the global call reference 
should interpret the message as pertaining to all call references associated 
with the appropriate data link connection identifier. See Figure\ 4\(hy5/Q.931. 
.RT
.LP
.rs
.sp 18P
.ad r
\fBFigure 4\(hy3/Q.931 [T57.931], p. 4\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 11P
.ad r
\fBFigure 4\(hy4/Q.931 [T58.931], p. 5\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.sp 2
.rs
.sp 32P
.ad r
\fBFigure 4\(hy5/Q.931 [T59.931], p. 6\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
4.4
	\fIMessage type\fR 
.sp 9p
.RT
.PP
The purpose of the message type is to identify the function of the message 
being sent. 
.PP
The message type is the third part of every message. The message type is 
coded as shown in 
Figure\ 4\(hy6/Q.931 and Table\ 4\(hy2/Q.931.
.PP
Bit 8 is reserved for possible future use as an extension bit.
.RT
.sp 2P
.LP
4.5
	\fIOther information elements\fR 
.sp 1P
.RT
.sp 1P
.LP
4.5.1
	\fICoding rules\fR 
.sp 9p
.RT
.PP
The coding of other information elements follows the coding
rules described below. These rules are formulated to allow each equipment 
which processes a message to find information elements important to it, 
and yet 
remain ignorant of information elements not important to that equipment.
.PP
Two categories of information elements are defined:
.RT
.LP
	a)
	single octet information elements (see Figure\ 4\(hy7a) and
b)/Q.931);
.LP
	b)
	variable length information elements (see
Figure\ 4\(hy7c)/Q.931).
.PP
For the information elements listed below, the coding of the
information element identifier bits is summarized in Table\ 4\(hy3/Q.931.
.PP
The descriptions of the information elements below are organized in
alphabetical order. However, there is a particular order of appearance 
for each information element in a message within each codeset (see\ \(sc\ 
4.5.2). The code 
values of the information element identifier for the variable length formats
are assigned in ascending numerical order, according to the actual order of
appearance of each information element in a message. This allows the receiving 
equipment to detect the presence or absence of a particular information 
element without scanning through an entire message. 
.PP
Single octet information elements may appear at any point in the
message. Two types of single octet information elements have been defined.
Type\ 1 elements provide the information element identification in bit
positions\ 7, 6,\ 5. The value \*Q010\*U in these bit positions is reserved for
Type\ 2 single octet elements.
.PP
Where the description of information elements in this Recommendation contains 
spare bits, these bits are indicated as being set to \*Q0\*U. In order 
to allow compatibility with future implementation, messages should not be
rejected simply because a spare bit is set to\ \*Q1\*U.
.PP
The second octet of a variable length information element indicates
the total length of the contents of that information element regardless 
of the coding of the first octet (i.e.,\ the length starting with octet\ 
3). It is the binary coding of the number of octets of the contents, with 
bit\ 1 as the least significant bit\ (2\(de). 
.PP
An optional variable\(hylength information element may be present, but
empty. For example, a SETUP message may contain a called party number
information element, the content of which is of zero length. This should be
interpreted by the receiver as equivalent to that information element being
absent. Similarly, an absent information element should be interpreted 
be the receiver as equivalent to that information element being empty. 
.PP
The following rules apply for the coding of variable length
information elements (octets\ 3\ etc.):
.RT
.LP
	a)
	 The first digit in the octet number identifies one octet or a group of 
octets. 
.LP
	b)
	Each octet group is a self contained entity. The internal
structure of an octet group may be defined in alternative ways.
.LP
	c)
	An octet group is formed by using some extension mechanism.
The preferred extension mechanism is to extend an octet\ (N) through the next
octet(s) (Na, Nb,\ etc.) by using bit\ 8 in each octet as an extension 
bit. The bit value\ \*Q0\*U indicates that the octet continues through 
the next octet. The 
bit value\ \*Q1\*U indicates that this octet is the last octet. If one 
octet\ (Nb) is present, also the preceding octets\ (N and\ Na) must be 
present. 
.LP
	In the format descriptions appearing in \(sc 4.5.5 etc., bit\ 8
is marked\ \*Q0/1\ ext\*U if another octet follows. Bit\ 8 is marked \*Q1\ 
ext\*U if 
this is the last octet in the
extension domain.
.LP
	Additional octets may be defined later (\*Q1\ ext\*U changed to
\*Q0/1\ ext\*U) and equipments shall be prepared to receive such additional 
octets although the equipment need not be able to interpret or act upon 
the content 
of these octets.
.LP
	d)
	In addition to the extension mechanism defined above, an
octet\ (N) may be extended through the next octet(s) (N1, N2\ etc.) by
indications in bits\ 7\(hy1 (of octet\ N).
.LP
	e)
	The mechanisms in c) and d) may be combined.
.LP
	f
)
	Optional octets are marked with asterisks
(*).
.bp
.LP
.rs
.sp 7P
.ad r
\fBFigure 4\(hy6/Q.931 [T60.931], p. 7\fR 
.sp 1P
.RT
.ad b
.RT
.ce
\fBH.T. [T61.931]\fR 
.ce
TABLE\ 4\(hy2/Q.931
.ce
\fBMessage types\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(66p) | lw(114p) .
8\ \ 7\ \ 6\ \ 5\ \ 4\ \ 3\ \ 2\ \ 1 .
0\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0 
escape to nationally specific message type; see
Note.
0\ \ 0\ \ 0\ \ -\ \ -\ \ -\ \ -\ \ - 
\fICall establishment\fR
\fImessage:\fR
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 0\ \ 1
\(em\ ALERTING
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 1\ \ 0
\(em\ CALL PROCEEDING
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 1\ \ 1\ \ 1
\(em\ CONNECT
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 1\ \ 1
\(em\ CONNECT ACKNOWLEDGE
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 1\ \ 1
\(em\ PROGRESS
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 1\ \ 0\ \ 1
\(em\ SETUP
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 0\ \ 1
\(em\ SETUP ACKNOWLEDGE
0\ \ 0\ \ 1\ \ -\ \ -\ \ -\ \ -\ \ -
\fICall information phase\fR
\fImessage:\fR
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 1\ \ 1\ \ 0
\(em\ RESUME
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 1\ \ 0
\(em\ RESUME ACKNOWLEDGE
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 1\ \ 0
\(em\ RESUME REJECT
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 1\ \ 0\ \ 1
\(em\ SUSPEND
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 0\ \ 1
\(em\ SUSPEND ACKNOWLEDGE
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 0\ \ 1
\(em\ SUSPEND REJECT
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 0\ \ 0
\(em\ USER INFORMATION
0\ \ 1\ \ 0\ \ -\ \ -\ \ -\ \ -\ \ -
\fICall clearing\fR
\fImessages:\fR
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 1\ \ 0\ \ 1
\(em\ DISCONNECT
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 0\ \ 1
\(em\ RELEASE
\ \ \ \ \ \ \ \ \ 1\ \ 1\ \ 0\ \ 1\ \ 0
\(em\ RELEASE COMPLETE
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 1\ \ 1\ \ 0
\(em\ RESTART
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 1\ \ 0
\(em\ RESTART ACKNOWLEDGE
0\ \ 1\ \ 1\ \ -\ \ -\ \ -\ \ -\ \ -
\fIMiscellaneous messages:\fR
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 0\ \ 0
\(em\ SEGMENT
\ \ \ \ \ \ \ \ \ 1\ \ 1\ \ 0\ \ 0\ \ 1
\(em\ CONGESTION CONTROL
\ \ \ \ \ \ \ \ \ 1\ \ 1\ \ 0\ \ 1\ \ 1
\(em\ INFORMATION
\ \ \ \ \ \ \ \ \ 0\ \ 0\ \ 0\ \ 1\ \ 0
\(em\ FACILITY
\ \ \ \ \ \ \ \ \ 0\ \ 1\ \ 1\ \ 1\ \ 0
\(em\ NOTIFY
\ \ \ \ \ \ \ \ \ 1\ \ 1\ \ 1\ \ 0\ \ 1
\(em\ STATUS
\ \ \ \ \ \ \ \ \ 1\ \ 0\ \ 1\ \ 0\ \ 1
\(em\ STATUS ENQUIRY
.TE
.LP
\fINote\fR
\ \(em\ When used, the message type is defined in the following octet(s),
according to the national specification.
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy2/Q.931 [T61.931], p. 8\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.LP
.rs
.sp 32P
.ad r
\fBFigure 4\(hy7/Q.931 [T62.931], p. 9\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 15P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [1T63.931]\fR 
.ce
TABLEAU\ 4\(hy3/Q.931
.ce
\fBInformation element identifier coding\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(60p) | cw(96p) | cw(36p) | lw(36p) .
 {
Bits
8\ \ 7\ \ 6\ \ 5\ \ 4\ \ 3\ \ 2\ \ 1
.
 }	Section reference	 {
Maximum length (octets)
(Note 1)
1\ \ 
:
\ \ 
:
\ \ 
:
\ \ -\ \ -\ \ -\ \ -
\fISingle octet information elements:\fR
\ \ \ 0\ \ 0\ \ 0\ \ -\ \ -\ \ -\ \ -
\ Reserved
\ \ \ 0\ \ 0\ \ 1\ \ -\ \ -\ \ -\ \ -
\ Shift (Note 2)
4.5.3/4.5.4
\ \ 1
\ \ \ 0\ \ 1\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0
\ More data
4.5.19
\ \ 1
\ \ \ 0\ \ 1\ \ 0\ \ 0\ \ 0\ \ 0\ \ 1
\ Sending complete
4.5.26
\ \ 1
\ \ \ 0\ \ 1\ \ 1\ \ -\ \ -\ \ -\ \ -
\ Congestion level
4.5.14 
\ \ 1
\ \ \ 1\ \ 0\ \ 1\ \ -\ \ -\ \ -\ \ -
\ Repeat indicator
4.5.23 
\ \ 1
0\ \ 
:
\ \ 
:
\ \ 
:
\ \ 
:
\ \ 
:
\ \ 
:
\ \ 
:
\fIVariable length information element:\fR
\ \ \ 0\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0
\ Segmented message
4.5.25
\ \ \ 0\ \ 0\ \ 0\ \ 0\ \ 1\ \ 0\ \ 0
\ Bearer capability (Note 2)
4.5.5\ 
\ 13
\ \ \ 0\ \ 0\ \ 0\ \ 1\ \ 0\ \ 0\ \ 0
\ Cause (Note 2)
4.5.12
\ 32
\ \ \ 0\ \ 0\ \ 1\ \ 0\ \ 0\ \ 0\ \ 0
\ Call identity
4.5.6\ 
\ 10
\ \ \ 0\ \ 0\ \ 1\ \ 0\ \ 1\ \ 0\ \ 0
\ Call state
4.5.7\ 
\ \ 3
\ \ \ 0\ \ 0\ \ 1\ \ 1\ \ 0\ \ 0\ \ 0
\ Channel identification (Note 2)
4.5.13
(Note 4)
\ \ \ 0\ \ 0\ \ 1\ \ 1\ \ 1\ \ 0\ \ 0
\ Facility (Note 2)
4.6.2\ 
(Note 4)
\ \ \ 0\ \ 0\ \ 1\ \ 1\ \ 1\ \ 1\ \ 0
\ Progress indicator (Note 2)
4.5.22
\ \ 4
\ \ \ 0\ \ 1\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0
\ Network\(hyspecific
facilities (Note 2)
4.5.20
(Note 4)
\ \ \ 0\ \ 1\ \ 0\ \ 0\ \ 1\ \ 1\ \ 1
\ Notification indicator
4.5.21
\ \ 3
\ \ \ 0\ \ 1\ \ 0\ \ 1\ \ 0\ \ 0\ \ 0
\ Display
4.5.15
34/82
\ \ \ 0\ \ 1\ \ 0\ \ 1\ \ 0\ \ 0\ \ 1
\ Date/time
4.6.1\ 
\ \ 8
\ \ \ 0\ \ 1\ \ 0\ \ 1\ \ 1\ \ 0\ \ 0
\ Keypad facility
4.5.17
\ 34
\ \ \ 0\ \ 1\ \ 1\ \ 0\ \ 1\ \ 0\ \ 0
\ Signal (Note 2)
4.5.27
\ \ 3
\ \ \ 0\ \ 1\ \ 1\ \ 0\ \ 1\ \ 1\ \ 0
\ Switchhook
4.6.5\ 
\ \ 3
\ \ \ 0\ \ 1\ \ 1\ \ 1\ \ 0\ \ 0\ \ 0
\ Feature activation 
4.6.3\ 
\ \ 4
\ \ \ 0\ \ 1\ \ 1\ \ 1\ \ 0\ \ 0\ \ 1
\ Feature indication 
4.6.4\ 
\ \ 5
\ \ \ 1\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0\ \ 0
\ Information rate
4.7.1\ 
\ \ 6
\ \ \ 1\ \ 0\ \ 0\ \ 0\ \ 0\ \ 1\ \ 0
\ End\(hyto\(hyend transit delay 
4.7.2\ 
\ 11
\ \ \ 1\ \ 0\ \ 0\ \ 0\ \ 0\ \ 1\ \ 1
\ Transit delay selection
and indication
4.7.7\ 
\ \ 5
\ \ \ 1\ \ 0\ \ 0\ \ 0\ \ 1\ \ 0\ \ 0
\ Packet layer binary parameters
4.7.3\ 
\ \ 3
\ \ \ 1\ \ 0\ \ 0\ \ 0\ \ 1\ \ 0\ \ 1
\ Packet layer window size
4.7.4\ 
\ \ 4
\ \ \ 1\ \ 0\ \ 0\ \ 0\ \ 1\ \ 1\ \ 0
\ Packet size 
4.7.5\ 
\ \ 4
\ \ \ 1\ \ 1\ \ 0\ \ 1\ \ 1\ \ 0\ \ 0
\ Calling party number
4.5.10
(Note 4)
\ \ \ 1\ \ 1\ \ 0\ \ 1\ \ 1\ \ 0\ \ 1
\ Calling party subaddress
4.5.11
\ 23
\ \ \ 1\ \ 1\ \ 1\ \ 0\ \ 0\ \ 0\ \ 0
\ Called party number
4.5.8\ 
(Note 4)
\ \ \ 1\ \ 1\ \ 1\ \ 0\ \ 0\ \ 0\ \ 1
\ Called party subaddress
4.5.9\ 
\ 23
\fR
\ \ \ 1\ \ 1\ \ 1\ \ 0\ \ 1\ \ 0\ \ 0
\ Redirecting number
4.7.6\ 
(Note 4)
\ \ \ 1\ \ 1\ \ 1\ \ 1\ \ 0\ \ 0\ \ 0
\ Transit network selection (Note 2)
4.5.28
(Note 4)
\ \ \ 1\ \ 1\ \ 1\ \ 1\ \ 0\ \ 0\ \ 1
\ Restart indicator
4.5.24
\ \ 3
\ \ \ 1\ \ 1\ \ 1\ \ 1\ \ 1\ \ 0\ \ 0
\ Low layer compatibility (Note 2)
4.5.18
\ 16
\ \ \ 1\ \ 1\ \ 1\ \ 1\ \ 1\ \ 0\ \ 1
\ High layer compatibility (Note 2)
4.5.16
\ \ 5
\ \ \ 1\ \ 1\ \ 1\ \ 1\ \ 1\ \ 1\ \ 0
\ User\(hyuser
4.5.29
35/131
\ \ \ 1\ \ 1\ \ 1\ \ 1\ \ 1\ \ 1\ \ 1
\ Escape for extension (Note 3)
 }	
_
.T&
lw(228p) .
.TE
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy3/Q.931 [1T63.931], p. 10\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [2T63.931]\fR 
.ce
\fINotes to Table 4\(hy3/Q.931\fR 
.LP
\fINote\ 1\fR 
\ \(em\ The length limits described for the variable length information
elements take into account only the present CCITT standardized coding
values. Future enhancements and expansions to this Recommendation will 
not be restricted to these limits. 
.LP
\fINote\ 2\fR 
\ \(em\ This information element may be repeated.
.LP
\fINote\ 3\fR 
\ \(em\ This escape mechanism is limited to codesets 5, 6 and 7 (see
\(sc\ 4.5.2). When the escape for extension is used, the information element
identifier is contained in octet\(hygroup\ 3 and the content of the information
element follows in the subsequent octets as shown in Figure\ 4\(hy8/Q.931.
.LP
\fINote\ 4\fR 
\ \(em\ The maximum length is network dependent.
.LP
\fINote\ 5\fR 
\ \(em\ The reserved values with bits 5\(hy8 coded \*Q0000\*U are for future
information elements for which comprehension by the receiver is required
(see \(sc\ 5.8.7.1).
.LP
\fBH.T. [T64.931]\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(144p) .
Bits
.T&
cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(24p) .
8	7	6	5	4	3	2	1	Octets 
.T&
lw(18p) | cw(126p) | lw(24p) .
	Escape for extension	
.T&
cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | cw(18p) | lw(24p) .
0	1	1	1	1	1	1	1	Octet  1
.T&
lw(144p) .
.T&
cw(144p) | lw(24p) .
 {
Length of information element contents
 }	Octet  2
.T&
cw(18p) | cw(126p) | lw(24p) .
1  ext	 {
Information element identifier
 }	Octet  3
.T&
cw(144p) | lw(24p) .
 {
Contents of information element
 }	Octet  4 Octet  etc.
.T&
cw(168p) .
 {
FIGURE 4\(hy8/Q.931
\fBInformation element format using escape for extension\fR
 }
.TE
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy3/Q.931 [2T63.931], p. 11\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.sp 5
.rs
.sp 16P
.ad r
\fBFigure 4\(hy8/Q.931 [T64.931], p. 12\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.sp 2
.sp 1P
.LP
4.5.2
	\fIExtensions of codesets\fR 
.sp 9p
.RT
.PP
There is a certain number of possible information element
identifier values using the formatting rules described in \(sc\ 4.5.1; 
128 from the variable length information element format and at least 8 
from the single octet information element format. 
.PP
One value in the single octet format is specified for shift operations 
described below. One other value in both the single octet and variable 
format is reserved. This leaves at least 133\ information element identifier 
values 
available for assignment.
.bp
.PP
It is possible to expand this structure to eight codesets of at least 133\ 
information element identifier values each. One common value in the single 
octet format is employed in each codeset to facilitate shifting from one 
codeset to another. The contents of this Shift information element identifies 
the codeset to be used for the next information element or elements. The 
codeset in use at any given time is referred to as the \*Qactive codeset\*U. By
convention, codeset\ 0 is the initially active codeset.
.PP
Two codeset shifting procedures are supported: locking shift and
non\(hylocking shift.
.PP
Codeset 5 is reserved for information elements reserved for national   use.
.PP
Codeset 6 is reserved for information elements specific to the local network 
(either public or private). 
.PP
Codeset 7 is reserved for user\(hyspecific information elements.
.PP
The coding rules specified in \(sc 4.5.1 shall apply for information
elements belonging to any active codeset.
.PP
Transitions from one active codeset to another (i.e., by means of the locking 
shift procedure) may only be made to a codeset with a higher numerical 
value than the codeset being left. 
.PP
An information element belonging to codesets 5, 6, or 7, may appear
together with information elements belonging to codeset\ 0 (being the active
codeset) by using the non\(hylocking shift procedure (see\ \(sc\ 4.5.4).
.PP
A user of network equipment shall have the capability to recognize a Shift 
information element and to determine the length of the following 
information element, although the equipment need not be able to interpret 
and act upon the content of the information element. This enables the equipment 
to determine the start of a subsequent information element. 
.PP
Codeset 7 information element shall be handled according to the
procedures for unrecognized information elements (see\ \(sc\ 5.8.7.1) by 
the first exchange in the local network, unless allowed by a future service 
definition, bilateral agreement, or provision is made to support this across 
the local 
network for a specific user.
.PP
Codeset 6 is reserved for information elements specific to the local network 
(either public or private). As such they do not have significance 
across the boundaries between local networks, or across a national, or
international boundary. Therefore, codeset\ 6 information elements shall be
handled according to the procedures for unrecognized information elements
(see\ \(sc\ 5.8.7.1) beyond local network boundary, unless allowed by bilateral
agreement.
.PP
Codeset 5 is reserved for information elements reserved for national use. 
As such they do not have significance across an international boundary. 
Therefore, codeset\ 5 information elements shall be handled according to the
procedures for unrecognized information elements (see\ \(sc\ 5.8.7.1) at 
the first exchange beyond the international boundary, unless there are 
bilateral 
agreements to the contrary.
.RT
.sp 1P
.LP
4.5.3
	\fILocking shift procedure\fR 
.sp 9p
.RT
.PP
The locking shift procedure employs an information element to
indicate the new active codeset. The specified codeset remains active until
another locking shift information element is encountered which specifies the
use of another codeset. For example, codeset\ 0 is active at the start of
message content analysis. If a locking shift to codeset\ 5 is encountered, 
the next information elements will be interpreted according to the information 
element identifiers assigned in codeset\ 5, until another shift information
element is encountered.
.PP
This procedure is used only to shift to a higher order codeset than
the one being left.
.PP
The 
locking shift
is valid only within that message which
contains the locking Shift information element. At the start of every message 
content analysis, the active codeset is codeset\ 0. 
.PP
The locking Shift information element uses the single octet
information element format and coding shown in Figure\ 4\(hy9/Q.931
and Table\ 4\(hy4/Q.931.
.bp
.RT
.LP
.rs
.sp 16P
.ad r
\fBFigure 4\(hy9/Q.931 [T65.931], p. 13\fR 
.sp 1P
.RT
.ad b
.RT
.ce
\fBH.T. [T66.931]\fR 
.ce
TABLE\ 4\(hy4/Q.931
.ce
\fBLocking Shift information
.ce
element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(228p) .
.TE
.nr PS 9
.RT
.ad r
ne
\fBFigure 4\(hy4/Q.931 [T66.931], p. 14\fR 
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
4.5.4
	\fINon\(hylocking shift procedure\fR 
.sp 9p
.RT
.PP
The non\(hylocking shift procedure provides a temporary shift to the specified 
lower or higher codeset. The non\(hylocking shift procedure uses a 
single octet information element to indicate the codeset to be used to
interpret the next single information element. After the interpretation 
of the next single information element, the active codeset is again used 
for 
interpreting any following information elements. For example, codeset\ 0 is
active at the beginning of message content analysis. If a non\(hylocking 
shift to codeset\ 6 is encountered, only the next information element is 
interpreted 
according to the information element identifiers assigned in codeset\ 6. 
After this information element is interpreted, codeset\ 0 will again be 
used to 
interpret the following information elements. A non\(hylocking Shift information 
element indicating the current codeset shall not be regarded as an error. 
.bp
.PP
A locking Shift information element shall not follow directly on a
non\(hylocking Shift information element. If this combination is received, it
shall be interpreted as though a locking Shift information element only had
been received.
.PP
The non\(hylocking Shift information element uses the single octet
information element format and coding shown in Figure\ 4\(hy10/Q.931 and
Table\ 4\(hy5/Q.931.
.RT
.LP
.rs
.sp 15P
.ad r
\fBFigure 4\(hy10/Q.931 [T67.931], p. 15\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.sp 5
.ce
\fBH.T. [T68.931]\fR 
.ce
TABLE\ 4\(hy5/Q.931
.ce
\fBNon\(hylocking Shift information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(228p) .
.TE
.nr PS 9
.RT
.ad r
ne
\fBTableau 4\(hy5/Q.931 [T68.931], p. 16\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
4.5.5
	\fIBearer capability\fR 
.sp 9p
.RT
.PP
The purpose of the Bearer capability information element is to
indicate a requested Recommendation\ I.231\ [6] bearer service to be provided 
by the network. It contains only information which \fImay\fR be used by 
the network 
(see Annex\ L). The use of the bearer capability information element in 
relation to compatibility checking is described in Annex\ B. 
.PP
The Bearer capability information element is coded as shown in
Figure\ 4\(hy11/Q.931 and Table\ 4\(hy6/Q.931.
.PP
Examples of the coding of the Bearer capability information element is 
shown in Annex\ H. 
.PP
No default bearer capability may be assumed by the absence of this
information element.
.PP
The maximum length of this information element is 13\ octets when CCITT 
standard coding is used. 
.PP
\fINote\fR \ \(em\ Future extensions to the codings of the Bearer capability
information element should not be in conflict with the currently defined 
coding of the Low layer compatibility information element (see\ \(sc\ 4.5.18). 
.RT
.sp 1P
.LP
4.5.6
	\fICall identity\fR 
.sp 9p
.RT
.PP
The purpose of the Call identity information element is to identify the 
suspended call. The call identity provided by the user is guaranteed by 
the network to be unique over the user\(hynetwork interface on which the 
user 
resides. The call identity is assigned at the start of the call suspension, 
and is available for re\(hyuse after the resume procedure has completed 
successfully. 
.PP
The Call identity information element is coded as shown in
Figure\ 4\(hy12/Q.931.
.PP
The default maximum length of this information element is ten
octets.
.RT
.sp 1P
.LP
4.5.7
	\fICall state\fR 
.sp 9p
.RT
.PP
The purpose of the Call state information element is to describe
the current status of a call, (see\ \(sc\ 2.1) or an access connection 
(see\ \(sc\ 2.2) or a global interface state (see\ \(sc\ 2.4). 
.PP
The Call state information element is coded as shown in
Figure 4\(hy13/Q.931 and Table\ 4\(hy7/Q.931.
.PP
The maximum length of this information element is three octets when
CCITT standard coding is used.
.RT
.sp 1P
.LP
4.5.8
	\fICalled party number\fR 
.sp 9p
.RT
.PP
The purpose of the Called party number information element is to
identify the called party of a call.
.PP
The Called party number information element is coded as shown in
Figure 4\(hy14/Q.931 and Table\ 4\(hy8/Q.931.
.PP
The maximum length of this information element is network
dependent.
.RT
.sp 1P
.LP
4.5.9
	\fICalled party subaddress\fR 
.sp 9p
.RT
.PP
The purpose of the Called party subaddress information
element is to identify the subaddress of the called party of a call. For the
definition of subaddress see Recommendation\ I.330\ [18].
.PP
The Called party subaddress is coded as shown in Figure 4\(hy15/Q.931
and Table 4\(hy9/Q.931.
.PP
The maximum length of this information element is 23 octets.
.bp
.RT
.LP
.rs
.sp 47P
.ad r
\fBFigure 4\(hy11/Q.931 + Notes [T69.931], p. 17\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T70.931]\fR 
.ce
TABLE\ 4\(hy6/Q.931\ (Sheet\ 1\ of\ 8)
.ce
\fBBearer capability information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(228p) .
\fICoding standard (octet 3):\fR
Bits 7\ \ 6 0\ \ 0 CCITT standardized coding as described below
0\ \ 1 reserved for other international standards (Note)
1\ \ 0 national standard (Note)
 {
1\ \ 1
standard defined for the network (either public or private)
present on the network side of the interface (Note)
 }
.TE
.LP
\fINote\fR
\ \(em\ These other coding standards should be used only when the
desired bearer capability can not be represented with the CCITT\(hystandardized
coding.
 }
.TS
center box ;
lw(228p) .
\fIInformation transfer capability (octet 3)\fR
Bits 5\ \ 4\ \ 3\ \ 2\ \ 1
 0\ \ 0\ \ 0\ \ 0\ \ 0 speech
0\ \ 1\ \ 0\ \ 0\ \ 0 unrestricted digital information
0\ \ 1\ \ 0\ \ 0\ \ 1 restricted digital information
1\ \ 0\ \ 0\ \ 0\ \ 0 3.1 kHz audio
1\ \ 0\ \ 0\ \ 0\ \ 1 7 kHz audio
1\ \ 1\ \ 0\ \ 0\ \ 0 Video
All other values are reserved.
\fITransfer mode (octet 4)\fR
Bits 7\ \ 6
0\ \ 0 circuit mode
1\ \ 0 packet\(hymode
All other values are reserved.
.TE
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy6/Q.931 (feuillet 1 sur 8) [T70.931], p. 18\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 17P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T71.931]\fR 
.ce
TABLE\ 4\(hy6/Q.931\ (Sheet\ 2\ of\ 8)
.ce
\fBBearer capability information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(228p) .
\fIInformation transfer rate (octets 4 and 4b, bits 5 to 1)\fR
Bits 5\ \ 4\ \ 3\ \ 2\ \ 1
\fICircuit mode\fR
\fIPacket\(hymode\fR
0\ \ 0\ \ 0\ \ 0\ \ 0 \(em This code shall be used for packet mode calls
1\ \ 0\ \ 0\ \ 0\ \ 0 64 kbit/s 
\(em 1\ \ 0\ \ 0\ \ 0\ \ 1
2 \(mu 64 kbit/s \(em 1\ \ 0\ \ 0\ \ 1\ \ 1
384 kbit/s \(em 1\ \ 0\ \ 1\ \ 0\ \ 1
1536 kbit/s \(em 1\ \ 0\ \ 1\ \ 1\ \ 1
1920 kbit/s \(em
All other values are reserved.
.TE
.LP
\fINote 1\fR
\ \(em\ When octet 4b is omitted, the bearer capability is
bidirectional symmetric at the information transfer rate specified in octet\ 4. When octet 4b is included, the information transfer rate in octet\ 4 refers to the origination \(ra destination direction.
.LP
\fINote 2\fR
\ \(em\ When the information transfer rate 2 \(mu 64 kbit/s is used, the
coding of octets\ 3 and\ 4 refer to both 64\ kbit/s channels.
.TS
box center ;
lw(228p) .
\fIStructure (octet 4a)\fR
Bits 7\ \ 6\ \ 5
0\ \ 0\ \ 0 default (see Note 1)
0\ \ 0\ \ 1 8 kHz integrity (Note 2)
1\ \ 0\ \ 0 service data unit integrity
1\ \ 1\ \ 1 unstructured
.TE
.LP
\fINote 1\fR
\ \(em\ If octet 4a is omitted, or the structure field is coded
\*Q000\*U, then the value of the structure attribute is according to the
following:

.TS
center box ;
lw(228p) .
\fITransfer mode\fR
\fITransfer capability\fR
\fIStructure\fR
circuit speech 8 kHz integrity
circuit unrestricted digital 8 kHz integrity
circuit restricted digital 8 kHz integrity
circuit audio 8 kHz integrity
circuit video 8 kHz integrity
packet unrestricted digital service data unit integrity 
.TE
.LP
\fINote 2\fR
\ \(em\ When the information transfer rate 2 \(mu 64 kbit/s is
used, 8\ kHz integrity with Restricted Differential Time Delay (RDTD) is
offered.
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy6/Q.931 (feuillet 2 sur 8) [T71.931], p. 19\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 12P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T72.931]\fR 
.ce
TABLE\ 4\(hy6/Q.931\ (Sheet\ 3\ of\ 8)
.ce
\fBBearer capability information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(228p) .
\fIConfiguration (octet 4a)\fR
Bits 4\ \ 3
0\ \ 0 point\(hyto\(hypoint
All other values are reserved.
.TE
.LP
\fINote\fR
\ \(em\ If octet 4a is omitted, the configuration is assumed to be
point\(hyto\(hypoint.
.TS
center box ;
lw(228p) .
\fIEstablishment (octet 4a)\fR
Bits 2\ \ 1
0\ \ 0 demand
All other values are reserved.
.TE
.LP
\fINote\fR
\ \(em\ If octet 4a is omitted, the method of establishment is
assumed to be \*Qdemand\*U.
.LP
\fISymmetry (octet 4b)\fR
Bits 7\ \ 6
0\ \ 0 bidirectional symmetric
All other values are reserved.
.LP
\fINote\fR
\ \(em\ If octet 4b is omitted, bidirectional symmetric is
assumed.
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy6/Q.931 (feuillet 3 sur 8) [T72.931], p. 20\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 22P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T73.931]\fR 
.ce
TABLE\ 4\(hy6/Q.931\ (Sheet\ 4\ of\ 8)
.ce
\fBBearer capability information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.LP
\fIUser information layer 1 protocol (octet 5)\fR
Bits 5\ \ 4\ \ 3\ \ 2\ \ 1
.LP
0\ \ 0\ \ 0\ \ 0\ \ 1
CCITT standardized rate adaption V.110/X.30. This
implies the presence of octet 5a and optionally octets 5b, 5c and 5d as
defined below.
.LP
0\ \ 0\ \ 0\ \ 1\ \ 0
Recommendation G.711 \(*m\(hylaw [10]
.LP
0\ \ 0\ \ 0\ \ 1\ \ 1
Recommendation G.711 A\(hylaw [10]
.LP
0\ \ 0\ \ 1\ \ 0\ \ 0
Recommendation G.721 [11] 32 kbit/s ADPCM and
Recommendation I.460
.LP
0\ \ 0\ \ 1\ \ 0\ \ 1
Recommendations G.722 [12] and G.725 [35] 7 kHz audio
.LP
0\ \ 0\ \ 1\ \ 1\ \ 0
Recommendation H.261 [13] for 384 kbit/s video
.LP
0\ \ 0\ \ 1\ \ 1\ \ 1
Non\(hyCCITT standardized rate adaption. This implies
the presence of octet 5a and, optionally, octets 5b, 5c and 5d. The use
of this code point indicates that the user rate specified in octet 5a is
defined in accordance with the non\(hyCCITT standardized rate adoption scheme.
Additionally, octets 5b, 5c and 5d, if present, are defined consistent
with the specified rate adoption.
.LP
0\ \ 1\ \ 0\ \ 0\ \ 0
CCITT standardized rate adaption V.120 [9]. This
implies the presence of octets 5a and 5b as defined below, and optionally
octets\ 5c and\ 5d.
.LP
0\ \ 1\ \ 0\ \ 0\ \ 1
CCITT standardized rate adaption X.31 [14] HDLC flag
stuffing.
.LP
All other values are reserved.
.LP
\fINote\fR
\ \(em\ If the transfer mode is \*Qcircuit mode\*U, and if the
information transfer capability is \*Qunrestricted digital information\*U or
\*Qrestricted digital information\*U, and if the user information layer 1 protocol is not to be identified to the network, octet 5 shall be omitted. If
the transfer mode is packet mode, octet 5 may be omitted. Otherwise, octet\ 5
shall be present.
.LP
\fISynchronous/asynchronous (octet 5a)\fR
Bit
7
.LP
0
Synchronous
.LP
1
Asynchronous
.LP
\fINote\fR
\ \(em\ Octets 5b\(hy5d may be omitted in case of synchronous user
rates.
.LP
\fINegotiation (octet 5a)\fR
.LP
Bit
6
.LP
0
In\(hyband negotiation not possible
.LP
1
In\(hyband negotiation possible
.LP
\fINote\fR
\ \(em\ See Recommendations V.110 [7] and
X.30 [8].
.nr PS 9
.RT
.ad r
\fBTableau 4\(hy6/Q.931 (feuillet 4 sur 8) [T73.931], p. 21\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 10P
.ad r
BLANC
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T74.931]\fR 
.ce
TABLE\ 4\(hy6/Q.931\ (Sheet\ 5\ of\ 8)
.ce
\fBBearer capability information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.LP
\fIUser rate (octet 5a)\fR
.LP
Bits
5\ \ 4\ \ 3\ \ 2\ \ 1
.LP
0\ \ 0\ \ 0\ \ 0\ \ 0
rate is indicated by E\(hybits specified in Recommendation
I.460 [15]
.LP
0\ \ 0\ \ 0\ \ 0\ \ 1
0.6 kbit/s Recommendations V.6 [16] and X.1 [17]
.LP
0\ \ 0\ \ 0\ \ 1\ \ 0
1.2 kbit/s Recommendation V.6
.LP
0\ \ 0\ \ 0\ \ 1\ \ 1
2.4 kbit/s Recommendations V.6 and X.1
.LP
0\ \ 0\ \ 1\ \ 0\ \ 0
3.6 kbit/s Recommendation V.6
.LP
0\ \ 0\ \ 1\ \ 0\ \ 1
4.8 kbit/s Recommendations V.6 and X.1
.LP
0\ \ 0\ \ 1\ \ 1\ \ 0
7.2 kbit/s Recommendation V.6
.LP
0\ \ 0\ \ 1\ \ 1\ \ 1
8 kbit/s Recommendation I.460
.LP
0\ \ 1\ \ 0\ \ 0\ \ 0
9.6 kbit/s Recommendations V.6 and X.1
.LP
0\ \ 1\ \ 0\ \ 0\ \ 1
14.4 kbit/s Recommendation V.6
.LP
0\ \ 1\ \ 0\ \ 1\ \ 0
16 kbit/s Recommendation I.460
.LP
0\ \ 1\ \ 0\ \ 1\ \ 1
19.2 kbit/s Recommendation V.6
.LP
0\ \ 1\ \ 1\ \ 0\ \ 0
32 kbit/s Recommendation I.460
.LP
0\ \ 1\ \ 1\ \ 1\ \ 0
48 kbit/s Recommendations V.6 and X.1
.LP
0\ \ 1\ \ 1\ \ 1\ \ 1
56 kbit/s Recommendation V.6
.LP
1\ \ 0\ \ 1\ \ 0\ \ 1
0.1345 kbit/s Recommendation X.1
.LP
1\ \ 0\ \ 1\ \ 1\ \ 0
0.100 kbit/s Recommendation X.1
.LP
1\ \ 0\ \ 1\ \ 1\ \ 1
0.075/1.2 kbit/s Recommendations V.6 and X.1 (Note)
.LP
1\ \ 1\ \ 0\ \ 0\ \ 0
1.2/0.075 kbit/s Recommendations V.6 and X.1 (Note)
.LP
1\ \ 1\ \ 0\ \ 0\ \ 1
0.050 kbit/s Recommendations V.6 and X.1
.LP
1\ \ 1\ \ 0\ \ 1\ \ 0
0.075 kbit/s Recommendations V.6 and X.1
.LP
1\ \ 1\ \ 0\ \ 1\ \ 1
0.110 kbit/s Recommendations V.6 and X.1
.LP
1\ \ 1\ \ 1\ \ 0\ \ 0
0.150 kbit/s Recommendations V.6 and X.1
.LP
1\ \ 1\ \ 1\ \ 0\ \ 1
0.200 kbit/s Recommendations V.6 and X.1
.LP
1\ \ 1\ \ 1\ \ 1\ \ 0
0.300 kbit/s Recommendations V.6 and X.1
.LP
1\ \ 1\ \ 1\ \ 1\ \ 1
12 kbit/s Recommendation V.6
.LP
All other values are reserved.
.LP
\fINote\fR
\ \(em\ The first rate is the transmit rate in the forward direction of the call. The second rate is the transmit rate in the backward
direction of the call.
.LP
\fIOctet 5b for V.110/X.30 rate adaption\fR
.LP
\fIIntermediate rate (octet 5b)\fR
.LP
Bits
7\ \ 6
.LP
0\ \ 0
Not used
.LP
0\ \ 1
8 kbit/s
.LP
1\ \ 0
16 kbit/s
.LP
1\ \ 1
32 kbit/s
.LP
\fINetwork independent clock (NIC) on transmission (Tx) (octet 5b)\fR
\fI(Note 1)\fR
.LP
Bit
5
.LP
0
Not required to send data with network independent clock
.LP
1
Required to send data with network independent clock
.LP
\fINote 1\fR
\ \(em\ Refers to transmission in the forward direction of the
call.
.LP
 }
.LP
\ \(em\ See Recommendations V.110 and X.30.
 }
.RT
.ad r
\fBTableau 4\(hy6/Q.931 (feuillet 5 sur 8) [T74.931], p. 22\fR 
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [T75.931]\fR 
.ce
TABLE\ 4\(hy6/Q.931\ (Sheet\ 6\ of\ 8)
.ce
\fBBearer capability information element\fR 
.ps 9
.vs 11
.nr VS 11
.nr PS 9

[unable to convert the rest of this appendix ]