delim @@
| 5i'
|
The format of the circuit state indicator parameter field is shown in Figure 15/Q.763. |
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|
3.12 |
Circuit state indicator |
Figure 15/Q.763, p. |
The number of octets in the circuit state indicator parameter field is equal to the specified range + 1. Each circuit state indicator octet is associated with a circuit identification code such that octet n is associated with circuit identification code m+n--1, where m is the circuit identification code contained in the message.
|
The following codes are used in each circuit state indicator octet. a) for bits D C = 0 0 bits B A: Maintenance blocking state 0 0 transient 0 1 spare 1 0 spare 1 1 unequipped bits E-H: Spare b) for bits D C not equal to 0 0 bits B A: Maintenance blocking state 0 0 no blocking (active) 0 1 locally blocked 1 0 remotely blocked 1 1 locally and remotely blocked bits D C: Call processing state 0 1 circuit incoming busy 1 0 circuit outgoing busy 1 1 idle bits F E: Hardware blocking state (Note) 0 0 no blocking (active) 0 1 locally blocked 1 0 remotely blocked 1 1 locally and remotely blocked bits G-H: Spare Note -- If bits F E are not coded 0 0, bits D C must be coded 1 1. |
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|
3.13 |
Closed user group interlock code The format of the closed user group interlock code parameter field |
is shown in Figure 16/Q.763. |
Figure 16/Q.763, p.
The following codes are used in the subfields of the closed user group interlock code parameter field:
a) Network identity (NI) (octets 1 and 2)
Each digit is coded in the binary coded decimal representation from 0 to 9.
If the first digit of this field is coded 0 or 9, the TCC (Telephony Country Code) follows in the second to fourth NI digits (the most significant TCC digit is in the 2nd NI digit). If the TCC is one or two digits long, the excess digit(s) is inserted with the code for RPOA or network identification, if necessary. If octet 2 is not required, it is coded all 0.
Coding of the first digit as 1 or 8 is excluded.
If the first digit is not 0, 9, 1 or 8 this field contains a DNIC (Data Network Identification Code) as defined in Recommendation X.121.
b) Binary code (octets 3 and 4)
A code allocated to a closed user group administered by a particular ISDN or data network. Bit 8 of octet 3 is the most significant and bit 1 of octet 4 is the least significant.
|
3.14 |
Connected number The format of the connected number parameter field corresponds to the format shown in Figure 17/Q.763. Figure 17/Q.763, p. The following codes are used in the subfields of the connected number parameter field: a) Odd/even indicator: see § 3.7 a) b) Nature of address indicator: see § 3.7 b) c) Numbering plan indicator: see § 3.7 d) d) Address presentation restricted indicator: see § 3.8 e) e) Screening indicator: see § 3.8 f) f) Address signal: see § 3.8 g) g) Filler: see § 3.7 h). |
|
|
3.15 |
Connection request The format of the connection request parameter field is shown in Figure 18/Q.763. The following codes are used in the subfields of the connection request parameter field: a) Local reference A code indicating the local reference allocated by the signalling connection control part to the end-to-end |
connection.
|
b) A code c) A code d) |
Point code identifying the signalling point at which the connection request originated. Protocol class identifying in pure binary representation, the protocol class requested for the end-to-end connection. Credit |
A code identifying in pure binary representation the window size requested for the end-to-end connection.
|
3.16 |
Continuity indicators The format of the continuity indicators parameter field is shown in Figure 19/Q.763. |
Figure 18/Q.763, p. |
||
|
Figure 19/Q.763, p. |
||||
|
The following codes are used in the continuity indicators parameter field. bit A: Continuity indicator 0 continuity check failed 1 continuity check successful bits B-H: Spare |
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|
3.17 |
End of optional parameters indicator |
The last optional parameter field of a message is followed by the end of optional parameters indicator, which occupies a one octet field containing all zeros.
3.18 Event information
The format of the event information parameter field is shown in Figure 20/Q.763.
|
The following codes are used in the event indicator parameter field: bits GFEDCBA: Event indicator 0000000 spare 0000001 ALERTING 0000010 PROGRESS 0000011 in-band information of an appropriate pattern is now available 0000100 call forwarded on busy 0000101 call forwarded on no reply 0000110 call forwarded unconditional 0000111 | o spare 1111111 bit H: Event presentation restricted indicator 0 no indication 1 presentation restricted |
Figure 20/Q.763, p. |
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|
3.19 |
Facility indicator The format of the facility indicator parameter field is shown in Figure 21/Q.763. |
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|
Figure 21/Q.763, p. |
||||
|
The following codes are used in the facility indicator parameter field. 00000000 spare 00000001 spare 00000010 user-to-user service |
|
00000011 to 11111111 |
spare |
||||
|
3.20 |
Forward The format of |
call indicators the forward call |
indicators parameter field is shown in Figure 22/Q.763. |
|
The following codes are used in the forward call indicators parameter field: bit A: National/international call indicator 0 call to be treated as a national call 1 call to be treated as an international call |
Figure 22/Q.763, p. |
This bit can be set to any value in the country of origin. In the international network this bit is not checked. In the destination country, calls from the international network will have this bit set to 1.
|
bits 0 |
0 |
C |
B: End-to-end method indicator (Note) no end-to-end method available (only link-by-link method available) |
|||||
|
0 1 1 |
1 0 1 |
pass along method available SCCP method available pass along and SCCP methods available |
|
bit 0 1 bit 0 1 bit 0 1 bits 0 0 1 1 bit 0 |
D: Interworking indicator (Note) no interworking encountered (No. 7 signalling all the way) interworking encountered E: End-to-end information indicator (Note) no end-to-end information available end-to-end information available F: ISDN user part indicator (Note) ISDN user part not used all the way ISDN user part used all the way H G: ISDN user part preference indicator 0 ISDN user part preferred all the way 1 ISDN user part not required all the way 0 ISDN user part required all the way 1 spare I: ISDN access indicator originating access non-ISDN |
|
1 bits 0 0 1 1 |
originating access ISDN K J: SCCP method indicator 0 no indication 1 connectionless method available 0 connection oriented method available 1 connectionless and connection oriented |
methods available |
||
|
bit bits |
L: Spare M-P: Reserved for national use |
Note -- Bits B-F and J-K constitute the protocol control indicator.
3.21 Information indicators
The format of the information indicators parameter field is shown in Figure 23/Q.763.
|
The following codes are used in the information indicators parameter field: bits B A: Calling party address response indicator 0 0 calling party address not included 0 1 calling party address not available 1 0 spare 1 1 calling party address included bit C: Hold provided indicator (national use) 0 hold not provided 1 hold provided bits E D: Spare bit F: Calling party's category response indicator 0 calling party's category not included 1 calling party's category included bit G: Charge information response indicator (national use) 0 charge information not included 1 charge information included bit H: Solicited information indicator 0 solicited 1 unsolicited bits I-P: Spare |
Figure 23/Q.763, p. |
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|
3.22 |
Information request indicators The format of the information request indicators parameter field is shown in |
Figure 24/Q.763. |
|
The following codes are used in the information request indicators parameter field. bit A: Calling party address request indicator 0 calling party address not requested 1 calling party address requested bit B: Holding indicator (national use) 0 holding not requested 1 holding requested bit C: Spare bit D: Calling party's category request indicator 0 calling party's category not requested 1 calling party's category requested bit E: Charge information request indicator (national use) 0 charge information not requested 1 charge information requested bits G F: Spare bit H: Malicious call identification request indicator (national use) 0 malicious call identification not requested 1 malicious call identification requested bits I-P: Spare |
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|
3.23 |
Nature of connection indicators The format of the nature of connection indicators parameter field is shown in Figure 25/Q.763. Figure 25/Q.763, p. The following codes are used in the nature of connection indicators parameter field: bits B A: Satellite indicator 0 0 no satellite circuit in the connection 0 1 one satellite circuit in the connection 1 0 two satellite circuits in the connection 1 1 spare |
|
bits 0 0 1 1 |
0 1 0 1 |
D |
C: Continuity check indicator continuity check not required continuity check required on this circuit continuity check performed on a previous circuit spare |
|
bit 0 1 bits |
E: outgoing outgoing F-H: |
E: Echo control device indicator outgoing half echo control device not included outgoing half echo control device included F-H: Spare |
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|
3.24 |
Optional |
Optional backward call indicators |
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|
The |
format |
of the optional backward call indicators parameter |
field is shown in Figure 26/Q.763. |
|
Figure 26/Q.763, p. The following codes are used in the optional backward call indicators parameter field: bit A: In-band information indicator 0 no indication 1 in-band information or an appropriate pattern is now available bit B: Call forwarding may occur indicator 0 no indication 1 call forwarding may occur bits C-D: Spare bits E-H: Reserved for national use |
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|
3.25 |
Optional forward call indicators The format of the optional forward call indicators parameter field is shown in Figure 27/Q.763. Figure 27/Q.763, p. The following codes are used in the optional forward call indicators parameter field: bits B A: Closed user group call indicator 0 0 non-CUG call 0 1 spare 1 0 closed user group call, outgoing access allowed 1 1 closed user group call, outgoing access not allowed bit C-H: Spare |
|
|
3.26 |
Original called number The format of the original called number parameter field corresponds to the format shown in Figure 28/Q.763. |
The following codes are used in the subfields of the original called number parameter field: a) Odd/even indicator: see § 3.7 a)
|
b) c) d) e) f) |
Nature Numbering Address Address Filler: |
Nature of address indicator: see § 3.7 b) Numbering plan indicator: see § 3.7 d) Address presentation restricted indicator: see § 3.8 e) Address signal: see § 3.8 g) see § 3.7 h). |
|
3.27 |
Range and status The format of the range and status parameter field is shown in Figure 29/Q.763. |
Figure 28/Q.763, p. |
||
|
Figure 29/Q.763, p. |
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|
The following codes are used in the subfields of the range and status parameter field: a) Range |
A number in pure binary representation ranging from 0 to 255. Range code 0 indicates absence of the status field. The number represented by a non-zero range code +1 indicates the range of circuits affected by the message.
b) Status
The status subfield contains from 1 to 256 status bits numbered from 0 to 255. Status bit 0 is located in bit position 1 of the first status subfield octet. Other status bits follow in numerical order. The number of relevant status bits in a given status subfield is equal to range +1.
Each status bit is associated with a circuit identification code such that status bit n is associated with circuit identification code m+n, where m is the circuit identification code contained in the message.
The status bits are coded as follows:
-- in circuit group blocking messages 0 no indication
1 blocking
-- in circuit group blocking acknowledgement messages 0 no indication
1 blocking acknowledgement
-- in circuit group unblocking messages 0 no indication
1 unblocking
-- in circuit group unblocking acknowledgement messages 0 no indication
1 unblocking acknowledgement
-- in circuit group reset acknowledgement messages 0 not blocked for maintenance reasons
1 blocked for maintenance reasons
The number of circuits affected by a group supervision message is limited to 32 or less. For the group reset and query messages this requires that the range value be 31 or less. For the group blocking and unblocking messages the range value may be up to 255, but the number of status bits set to 1 must be 32 or less.
|
For the group blocking, unblocking and reset messages, range code 0 is reserved. |
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|
3.28 |
Redirecting number The format of the redirecting number parameter field corresponds to the format shown in Figure 28/Q.763. The following codes are used in the subfields of the redirecting number parameter field: a) Odd/even indicator: see § 3.7 a) b) Nature of address indicator: see § 3.7 b) c) Numbering plan indicator: see § 3.7 d) d) Address presentation restricted indicator: see § 3.8 e) e) Address signal: see § 3.8 g) f) Filler: see § 3.7 f). |
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|
3.29 |
Redirection information The format of the redirection information parameter field is shown in Figure 30/Q.763. |
The following codes are used in the redirection information parameter field:
|
bits 0 |
0 |
C |
0 |
B |
A: Redirecting indicator no redirection |
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|
0 0 0 1 1 1 1 |
0 1 1 0 0 1 1 |
1 0 1 0 1 0 1 |
call rerouted call rerouted, all redirection information presentation restricted call forwarded call forwarded, all redirection information presentation restricted call rerouted, redirection number presentation restricted call forwarded, redirection number presentation restricted spare |
bit D: Spare
|
bits 0 |
0 |
H |
0 |
G |
0 |
F |
E: Original redirection reasons unknown/not available |
|||||||||
|
0 0 0 0 |
0 0 0 1 |
0 1 1 0 |
1 0 1 0 |
user busy no reply unconditional |
| o spare
1 1 1 1
|
bits K J I: bit L: Spare bits P O N |
Redirection counter. Number of redirections the call has undergone expressed as M: Redirecting reason |
|
0 0 0 0 0 | o 1 |
0 0 0 0 1 1 |
0 0 1 1 0 spare 1 |
0 1 0 1 0 1 |
unknown/not available user busy no reply unconditional |
3.30 Redirection number
The format of the redirection number parameter field corresponds to the format shown in Figure 9/Q.763.
The following codes are used in the subfields of the redirection number parameter field:
|
3.31 |
a) b) c) d) e) f) |
Odd/even indicator: see § 3.7 a) Nature of address indicator: see § 3.7 b) Internal nerwork number indicator: see § 3.7 c) Numbering plan indicator: see § 3.7 d) Address signal: see § 3.8 f) Filler: see § 3.7 f). Signalling point code (national use) |
The format of the signalling point code parameter field is shown in Figure 31/Q.763.
Figure 31/Q.763, p.
|
3.32 |
The signalling point code is a pure binary representation of the code allocated to a node in the signalling network. Subsequent number The format of the subsequent number parameter field is shown in Figure 32/Q.763. Figure 32/Q.763, p. The following codes are used in the subfields of the subsequent number parameter field: a) Odd/even indicator: see § 3.7 a) b) Address signal: see § 3.7 e) c) Filler: see § 3.7 f). |
|
|
3.33 |
Suspend/resume indicators The format of the suspend/resume indicators parameter field is shown in Figure 33/Q.763. Figure 33/Q.763, p. The following codes are used in the suspend/resume indicators parameter field: bit A: Suspend/resume indicator 0: ISDN subscriber initiated 1: network initiated bits B-H: Spare |
|
3.34 |
Transit network selection (national use) The format of the transit network selection parameter field is shown in Figure 34/Q.763. Figure 34/Q.763, p. The following codes are used in the subfields of the transit network selection parameter field: a) Odd/even indicator 0 even number of digits 1 odd number of digits b) Type of network identification 000 CCITT-standardized identification 010 national network identification other reserved c) Network identification plan i) For CCITT-standardized identification 0000 unknown 0011 public data network identification code (DNIC), Recommendation X.121 0110 public land mobile network identification code (MNIC), Recommendation E.212 other spare ii) For national network identification This information is coded according to national specifications. d) Network identification This information is organized according to the network identification plan and the encoding principles given |
in § 3.8 f).
3.35 Transmission medium requirement
The format of the transmission medium requirement parameter field is shown in Figure 35/Q.763.
|
The following codes are used in the transmission medium requirement parameter field. 00000000 speech 00000001 spare 00000010 64 kbit/s unrestricted 00000011 3.1 kHz audio 00000100 alternate speech (service 2)/64 kbit/s unrestricted (service 1) (Note 1) 00000101 alternate 64 kbit/s unrestricted (service 1)/speech (service 2) (Note 2) 00000110 spare 00000111 reserved for 2 × 64 kbit/s unrestricted 00001000 reserved for 384 kbit/s unrestricted 00001001 reserved for 1536 kbit/s unrestricted 00001010 reserved for 1920 kbit/s unrestricted 00001011 to spare 11111111 Note 1 -- The initial mode is speech. Note 2 -- The initial mode is 64 kbit/s unrestricted. |
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|
3.36 |
User service information The format of the user service information parameter field is shown in Figure 36/Q.763. This format is the same |
as the bearer capability information element from Recommendation Q.931 and not all capabilities coded here are supported at this time.
|
The following codes are used in the subfields of the user service information parameter field: a) Extension indicator (ext) 0 octet continues through the next octet (e.g. octet 2 to 2a, 2a to 2b, 3 to 3a) 1 last octet |
Figure 36/Q.763, p. |
|
b) 00 01 10 11 Note |
Coding standard CCITT standardized coding as described below reserved for other international standards (Note) national standard (Note) standard defined for the network (either public or private) present on the network side of the interface -- These other coding standards should only be used when the desired bearer capability cannot be |
represented with the CCITT standardized coding.
|
c) 00000 01000 01001 10000 10001 11000 |
Information transfer capability speech unrestricted digital information restricted digital information 3.1 kHz audio 7 kHz audio video |
|
All other values are reserved d) Transfer mode 00 circuit mode 10 packet mode All other values are reserved e) Information transfer rate (octets 2 and 2b) | (Note 1) 00000 This code shall be used for packet-mode calls 10000 64 kbit/s 10001 2 × 64 kbit/s (Note 2) 10011 384 kbit/s 10101 1536 kbit/s 10111 1920 kbit/s All other values are reserved. Note 1 -- When octet 2b is omitted, the bearer capability is bidirectional symmetric at the information transfer |
rate specified in octet 2. When octet 2b is included, the information rate in octet 2 refers to the origination to destination direction.
|
Note 2 -- For this case, the coding of octets 1 and 2a refer to both 64 kbit/s circuits. f ) Structure 000 default (Note 1) 001 8 kHz integrity (Note 2) 100 service data unit integrity 111 unstructured All other values are reserved. |
Note 1 -- If octet 2a is omitted, or the structure field is coded 000, then the value of the structure attribute is according to the following:
Transfer mode Transfer capability Structure
|
circuit circuit circuit circuit circuit packet |
speech 8 kHz integrity unrestricted digital 8 kHz integrity restricted digital 8 kHz integrity audio 8 kHz integrity video 8 kHz integrity unrestricted digital service data unit |
integrity |
Note 2 -- When the information transfer rate 2 × 64 kbit/s is used, 8 kHz integrity with Restricted Differential Time Delay (RDTD) is offered.
g) Configuration
00 point-to-point All other values are reserved. If omitted, the configuration is assumed to be point-to-point.
h) Establishment
00 demand All other values are reserved. If omitted, the establishment is assumed to be demand.
i) Symmetry
|
00 bidirectional symmetric j) Layer identification 00 reserved |
All other values are reserved. If omitted, the symmetry is assumed to be |
01 user information layer 1 protocol
10 user information layer 2 protocol
11 user information layer 3 protocol
Note -- Bits 5-1 of the same octet represent the corresponding identification as per points k), l) and m) below. If octet 3, 4 or 5 is omitted, the corresponding user information protocol is assumed to be undefined.
k) User information layer 1 protocol identification
00001 CCITT standardized rate adaption V.110/X.30. This implies the presence of octet 3a defined in § 3.36 k) 1), and optionally octets 3b, 3c and 3d defined in § 3.36 k) 2) below.
|
00010 00010 00100 00101 00110 00111 |
Recommendation G.711 m-law Recommendation G.711 A-law Recommendation G.721 32 kbit/s ADPCM and Recommendation I.460 Recommendations G.722 and G.724 for 7 kHz audio Recommendation G.735 for 384 kbit/s video non-CCITT standardized rate adaption. This implies the presence of octet 3a, and optionally 3b, 3c |
and 3d. The use of this codepoint indicates that the user rate specified in octet 3a is defined in accordance with the non-CCITT standardized rate adaption scheme. Additionally, octets 3b, 3c and 3d, if present, are defined consistent with the specified rate adaption.
01000 CCITT standardized rate adaption V.120. This implies the presence of octet 3a defined in § 3.36 k) 1), octet 3b defined in § 3.36 k) 3), and optionally octets 3c and 3d defined in § 3.36 k) 2) below.
01001 CCITT standardized rate adaption X.31 HDLC flag stuffing. All other values are reserved.
Note -- Octet 3 shall be omitted if the transfer mode is ``circuit-mode'', the information transfer capability is ``unrestricted digital information'' or ``restricted digital information'' and the user information layer 1 protocol is not to be identified to the network; octet 3 may be omitted if the transfer mode is ``packet-mode''; otherwise octet 3 shall be present.
1) Octet 3a for layer 1 rate adaption | (see Figure 37/Q.763)
|
Figure 37/Q.763, p. |
|||
|
-- The synchronous/asynchronous indicator is coded: 0 synchronous 1 asynchronous Octets 3b to 3d may be omitted in case of synchronous |
synchronous user |
rates. |
-- The negotiation indicator is coded: 0 in-band negotiation not possible 1 in-band negotiation possible
Note -- See Recommendations V.110 and X.30
|
-- 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01110 01111 10101 10110 10111 11000 11001 11010 11011 11100 11101 11110 11111 |
The user rate is coded: rate indicated by E-bits Rec. I.460 0.6 kbit/s Rec. V.6 and X.1 1.2 kbit/s Rec. V.6 2.4 kbit/s Rec. V.6 and X.1 3.6 kbit/s Rec. V.6 4.8 kbit/s Rec. V.6 and X.1 7.2 kbit/s Rec. V.6 8.0 kbit/s Rec. I.460 9.6 kbit/s Rec. V.6 and X.1 14.4 kbit/s Rec. V.6 16.0 kbit/s Rec. I.460 19.2 kbit/s Rec. V.6 32.0 kbit/s Rec. I.460 48.0 kbit/s Rec. V.6 and X.1 56.0 kbit/s Rec. V.6 0.1345 kbit/s Rec. X.1 0.100 kbit/s Rec. X.1 0.075/1.2 kbit/s Rec. V.6 and X.1 (Note) 1.2/0.075 kbit/s Rec. V.6 and X.1 (Note) 0.050 kbit/s Rec. V.6 and X.1 0.075 kbit/s Rec. V.6 and X.1 0.110 kbit/s Rec. V.6 and X.1 0.150 kbit/s Rec. V.6 and X.1 0.200 kbit/s Rec. V.6 and X.1 0.300 kbit/s Rec. V.6 and X.1 12 kbit/s Rec. V.6 and X.1 All other |
other values are reserved. |
Note -- 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.
2) Octets 3b, 3c and 3d for Recommendations V.110/X.30 rate adaption (see Figure 38/Q.763)
|
-- 01 10 11 |
Intermediate rate indicator is coded: 8 kbit/s 16 kbit/s 32 kbit/s |
00 |
not used |
Figure 38/Q.763, p. |
-- Network independent clock (NIC) on transmission (TX) indicator is coded: 0 not required to send data with NIC
1 required to send data with NIC
Note -- Refers to transmission in the forward direction of the call, see Recommendations V.110 and X.30
-- Network independent clock (NIC) on reception (Rx) indicator is coded: 0 cannot accept data with NIC (i.e. sender does not support this optional procedure)
1 can accept data with NIC (i.e. sender does support this optional procedure)
Note -- Refers to transmission in the backward direction of the call, see Recommendations V.110 and X.30.
-- Flow control on transmission (Tx) indicator is coded: 0 not required to send data with flow control mechanism
1 required to send data with flow control mechanism
Note -- Refers to transmission in the forward direction of the call, see Recommendations V.110 and X.30.
-- Flow control on reception (Rx) indicator is coded: 0 cannot accept data with flow control mechanism (i.e. sender does not support this optional procedure)
|
1 can accept data with flow control mechanism (i.e. sender does support this optional procedure) Note -- See Recommendations V.110 and X.30. -- Number of stop bits indicator is coded: 00 not used 01 1 bit 10 1.5 bits 11 2 bits -- Number of data bits indicator, including parity bit if present, is coded: 00 not used 01 5 bits 10 7 bits 11 8 bits -- Parity indicator is coded: 000 odd 010 even 011 none 100 forced to 0 101 forced to 1 All other values are reserved -- Duplex mode indicator is coded: 0 half duplex 1 full duplex -- modem type indicator is coded according to network specific rules. 3) Octet 3b for Recommendation V.120 rate adaption | (see Figure 39/Q.763) |
-- Rate adaption header/no header indicator is coded: 0 rate adaption header not included
1 rate adaption header included
-- Multiple frame establishment support in data link indicator is coded: 0 multiple frame establishment not supported, only UI frames allowed
1 multiple frame establishment supported
-- Mode of operation indicator is coded: 0 bit transparent mode of operation
1 protocol sensitive mode of operation
-- Logical link identifier (LLI) negotiation indicator is coded: 0 default, LLI = 256 only
|
1 full protocol negotiation (Note) Note -- A connection over which protocol negotiation will be executed is indicated in bit 2 of octet 3b. -- Assignor/assignee indicator is coded: 0 message originator is ``default assignee'' 1 message originator is ``assignor only'' -- In-band/out-of-band negotiation indicator is coded: 0 negotiation is done with |
USER |
|
INFORMATION messages on a temporary signalling connection |
|
1 l) 00010 00110 |
negotiation is done in-band using logical link zero User information layer 2 protocol identification Recommendation Q.921 (I.441) Recommendation X.25, link level All other |
values are reserved. If the transfer mode is ``packet |
mode'', this octet shall be present. In other cases, the octet is present only if the protocol is to be identified to the network.
m) User information layer 3 protocol identification
00010 Recommendation Q.931 (I.451)
00110 Recommendation X.25, link level All other values are reserved. The octet is present only if the protocol is to be identified to the network.
|
3.37 |
User-to-user indicators The format of the user-to-user indicators parameter field is shown in Figure 40/Q.763. |
||
|
Figure 40/Q.763, p. |
|||
|
The following codes are used in the user-to-user indicators parameter field: bit A Type 0 request |
1 response
|
If bit A equals 0 (request): bits 0 0 no information 0 1 spare 1 0 request, not essential 1 1 request, essential bits E D: Service 2 0 0 no information 0 1 spare 1 0 request, not essential 1 1 request, essential bits G F: Service 3 0 0 no information 0 1 spare 1 0 request, not essential 1 1 request, essential bit H Spare If bit A equals 1 (response): bits |
C C |
B: B: |
Service 1 Service 1 |
||||
|
3.38 |
0 0 no information 0 1 not provided 1 0 provided 1 1 spare bits E D: Service 2 0 0 no information 0 1 not provided 1 0 provided 1 1 spare bits G F: Service 3 0 0 no information 0 1 not provided 1 0 provided 1 1 spare bit H Spare User-to-user information |
|
The format of the user-to-user information parameter is shown in Figure 41/Q.763. |
Figure 41/Q.763, p. |
The format of the user-to-user information parameter field is coded identically to the protocol discriminator plus user information field described in Recommendation Q.931, § 4.5.29.
In the following tables the format and coding of ISDN user part messages is specified. For each message, a list of the relevant parameters is given and for each parameter:
|
-- -- F = V = O = -- -- -- |
a reference to the section where the formatting and coding of the parameter content is specified; the type | f the parameter. The following types are used in the tables: mandatory fixed length parameter; mandatory variable length parameter; optional parameter of fixed or variable length; the length | f the parameter. The value in the table includes: for type F parameters | he length, in octets, of the parameter content; for type V parameters | he length, in octets, of the length indicator and of the parameter content. The |
minimum and the maximum length are indicated;
-- for type O parameters | he length, in octets, of the parameter name, length indicator and parameter content. For variable length parameters the minimum and maximum length is indicated.
For each message type, type F parameters and the pointers for the type V parameters must be sent in the order specified in the tables.
The routing label and circuit identification code fields, which are transmitted ahead of the message type field if required are not shown. Parameter names, pointers to mandatory variable fields and the optional part, and length indicators appear in the message in accordance with Figure 3/Q.763 and are not shown explicitly in Tables 5/Q.763 to 28/Q.763.
Tableau 5/Q.763 [T5.763], p. 28
Tableau 8/Q.763 [T8.763], p. 31
Tableau 9/Q.763 [T9.763], p. 32 Tableau 10/Q.763 [T10.763], p. 33
|
Blanc |
Tableau 14/Q.763 [T14.763], p. 37 Tableau 15/Q.763 [T15.763], p. 38 |
Tableau 16/Q.763 [T16.763], p. 39 Blanc
ANNEX A
(to Recommendation Q.763)
Interpretation of spare codes
This Annex describes interpretations which can be applied when a recognized parameter is received containing codes currently indicated as being spare in Recommendation Q.763. This situation can occur when an implementation in accordance to this Recommendation interworks with a future version of this Recommendation. The default interpretations for some of these cases are listed in Table A-1/Q.763.
For the remaining cases, listed in Table A-2/Q.763, there is no default which is considered appropriate. It is recommended that the entire parameter in these cases should be considered uninterpretable except as noted.
Actions taken after applying the default interpretation of unrecognized fields or after determining that an entire parameter should be considered uninterpretable are described in § 2.10.5.3 of Recommendation Q.764. Application of default interpretations is of particular interest when an unrecognized parameter value is passed on at an intermediate exchange or is used at a connection endpoint. However, other applications are not precluded.