5i' MONTAGE: REC.Q.763 EN-T | TE DE CETTE PAGE 3.12 Circuit state indicator The format of the circuit state indicator parameter field is shown in Figure 15/Q.763. 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 indi- cator 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 mes- sage. 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. 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 representa- tion 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 sig- nificant 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 S 3.7 a) b) Nature of address indicator: see S 3.7 b) c) Numbering plan indicator: see S 3.7 d) d) Address presentation restricted indicator: see S 3.8 e) e) Screening indicator: see S 3.8 f) f) Address signal: see S 3.8 g) g) Filler: see S 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 connec- tion request parameter field: a) Local reference A code indicating the local reference allocated by the sig- nalling connection control part to the end-to-end connection. b) Point code A code identifying the signalling point at which the con- nection request originated. c) Protocol class A code identifying in pure binary representation, the pro- tocol class requested for the end-to-end connection. d) Credit A code identifying in pure binary representation the win- dow size requested for the end-to-end connection. Figure 18/Q.763, p. 3.16 Continuity indicators The format of the continuity indicators parameter field is shown in Figure 19/Q.763. 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 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. Figure 20/Q.763, p. 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 pat- tern 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 indi- cator 0 no indication 1 presentation restricted 3.19 Facility indicator The format of the facility indicator parameter field is shown in Figure 21/Q.763. Figure 21/Q.763, p. The following codes are used in the facility indicator parame- ter field. 00000000 spare 00000001 spare 00000010 user-to-user service 00000011 to spare 11111111 3.20 Forward call indicators The format of the forward call indicators parameter field is shown in Figure 22/Q.763. Figure 22/Q.763, p. The following codes are used in the forward call indicators parameter field: bit A: National/international call indica- tor 0 call to be treated as a national call 1 call to be treated as an international call This bit can be set to any value in the country of origin. In the international network this bit is not checked. In the desti- nation country, calls from the international network will have this bit set to 1. bits C B: End-to-end method indica- tor (Note) 0 0 no end-to-end method available (only link-by-link method available) 0 1 pass along method available 1 0 SCCP method available 1 1 pass along and SCCP methods available bit D: Interworking indicator (Note) 0 no interworking encountered (No. 7 signalling all the way) 1 interworking encountered bit E: End-to-end information indicator (Note) 0 no end-to-end information available 1 end-to-end information available bit F: ISDN user part indicator (Note) 0 ISDN user part not used all the way 1 ISDN user part used all the way bits H G: ISDN user part preference indicator 0 0 ISDN user part preferred all the way 0 1 ISDN user part not required all the way 1 0 ISDN user part required all the way 1 1 spare bit I: ISDN access indicator 0 originating access non-ISDN 1 originating access ISDN bits K J: SCCP method indicator 0 0 no indication 0 1 connectionless method available 1 0 connection oriented method available 1 1 connectionless and connection oriented methods available bit L: Spare bits 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. Figure 23/Q.763, p. 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 indica- tor (national use) 0 charge information not included 1 charge information included bit H: Solicited information indicator 0 solicited 1 unsolicited bits I-P: Spare 3.22 Information request indicators The format of the information request indicators parameter field is shown in Figure 24/Q.763. Figure 24/Q.763, p. The following codes are used in the information request indi- cators parameter field. bit A: Calling party address request indi- cator 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 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 indi- cators 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 connec- tion 1 1 spare bits D C: Continuity check indica- tor 0 0 continuity check not required 0 1 continuity check required on this cir- cuit 1 0 continuity check performed on a previ- ous circuit 1 1 spare bit E: Echo control device indicator 0 outgoing half echo control device not included 1 outgoing half echo control device included bits F-H: Spare 3.24 Optional backward call indicators 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 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 S 3.7 a) b) Nature of address indicator: see S 3.7 b) c) Numbering plan indicator: see S 3.7 d) d) Address presentation restricted indicator: see S 3.8 e) e) Address signal: see S 3.8 g) f) Filler: see S 3.7 h). Figure 28/Q.763, p. 3.27 Range and status The format of the range and status parameter field is shown in Figure 29/Q.763. Figure 29/Q.763, p. 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 num- bered from 0 to 255. Status bit 0 is located in bit position 1 of the first status subfield octet. Other status bits follow in numer- ical 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 identifica- tion code such that status bit n is associated with circuit iden- tification 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 mes- sages 0 no indication 1 blocking acknowledgement - in circuit group unblocking messages 0 no indication 1 unblocking - in circuit group unblocking acknowledgement mes- sages 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. 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 redirect- ing number parameter field: a) Odd/even indicator: see S 3.7 a) b) Nature of address indicator: see S 3.7 b) c) Numbering plan indicator: see S 3.7 d) d) Address presentation restricted indicator: see S 3.8 e) e) Address signal: see S 3.8 g) f) Filler: see S 3.7 f). 3.29 Redirection information The format of the redirection information parameter field is shown in Figure 30/Q.763. Figure 30/Q.763, p. The following codes are used in the redirection information parameter field: bits C B A: Redirecting indicator 0 0 0 no redirection 0 0 1 call rerouted 0 1 0 call rerouted, all redirec- tion information presentation restricted 0 1 1 call forwarded 1 0 0 call forwarded, all redirec- tion information presentation restricted 1 0 1 call rerouted, redirection number presentation restricted 1 1 0 call forwarded, redirection number presentation restricted 1 1 1 spare bit D: Spare bits H G F E: Ori- ginal redirection reasons 0 0 0 0 unknown/not avail- able 0 0 0 1 user busy 0 0 1 0 no reply 0 0 1 1 unconditional 0 1 0 0 | o spare 1 1 1 1 bits K J I: Redirection counter. Number of redirections the call has undergone expressed as a binary number between 1 and 5. bit L: Spare bits P O N M: Redirecting reason 0 0 0 0 unknown/not avail- able 0 0 0 1 user busy 0 0 1 0 no reply 0 0 1 1 unconditional 0 1 0 0 | o spare 1 1 1 1 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 redirec- tion number parameter field: a) Odd/even indicator: see S 3.7 a) b) Nature of address indicator: see S 3.7 b) c) Internal nerwork number indicator: see S 3.7 c) d) Numbering plan indicator: see S 3.7 d) e) Address signal: see S 3.8 f) f) Filler: see S 3.7 f). 3.31 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. The signalling point code is a pure binary representation of the code allocated to a node in the signalling network. 3.32 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 subse- quent number parameter field: a) Odd/even indicator: see S 3.7 a) b) Address signal: see S 3.7 e) c) Filler: see S 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 specifica- tions. d) Network identification This information is organized according to the network identification plan and the encoding principles given in S 3.8 f). 3.35 Transmission medium requirement The format of the transmission medium requirement parameter field is shown in Figure 35/Q.763. Figure 35/Q.763, p. 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 x 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. 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. Figure 36/Q.763, p. The following codes are used in the subfields of the user ser- vice 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 b) Coding standard 00 CCITT standardized coding as described below 01 reserved for other international standards (Note) 10 national standard (Note) 11 standard defined for the network (either public or private) present on the network side of the interface (Note) Note - These other coding standards should only be used when the desired bearer capability cannot be represented with the CCITT standardized coding. c) Information transfer capability 00000 speech 01000 unrestricted digital information 01001 restricted digital information 10000 3.1 kHz audio 10001 7 kHz audio 11000 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 x 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 speci- fied 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 accord- ing to the following: Transfer mode Transfer capability Structure 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 Note 2 - When the information transfer rate 2 x 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 All other values are reserved. If omitted, the symmetry is assumed to be bidirec- tional symmetric. j) Layer identification 00 reserved 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 pro- tocol 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 S 3.36 k) 1), and optionally octets 3b, 3c and 3d defined in S 3.36 k) 2) below. 00010 Recommendation G.711 u-law 00010 Recommendation G.711 A-law 00100 Recommendation G.721 32 kbit/s ADPCM and Recommendation I.460 00101 Recommendations G.722 and G.724 for 7 kHz audio 00110 Recommendation G.735 for 384 kbit/s video 00111 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 S 3.36 k) 1), octet 3b defined in S 3.36 k) 3), and optionally octets 3c and 3d defined in S 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 "unres- tricted 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 Fig- ure 37/Q.763) Figure 37/Q.763, p. - The synchronous/asynchronous indicator is coded: 0 synchronous 1 asynchronous Octets 3b to 3d may be omit- ted in case of 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 - The user rate is coded: 00000 rate indicated by E-bits Rec. I.460 00001 0.6 kbit/s Rec. V.6 and X.1 00010 1.2 kbit/s Rec. V.6 00011 2.4 kbit/s Rec. V.6 and X.1 00100 3.6 kbit/s Rec. V.6 00101 4.8 kbit/s Rec. V.6 and X.1 00110 7.2 kbit/s Rec. V.6 00111 8.0 kbit/s Rec. I.460 01000 9.6 kbit/s Rec. V.6 and X.1 01001 14.4 kbit/s Rec. V.6 01010 16.0 kbit/s Rec. I.460 01011 19.2 kbit/s Rec. V.6 01100 32.0 kbit/s Rec. I.460 01110 48.0 kbit/s Rec. V.6 and X.1 01111 56.0 kbit/s Rec. V.6 10101 0.1345 kbit/s Rec. X.1 10110 0.100 kbit/s Rec. X.1 10111 0.075/1.2 kbit/s Rec. V.6 and X.1 (Note) 11000 1.2/0.075 kbit/s Rec. V.6 and X.1 (Note) 11001 0.050 kbit/s Rec. V.6 and X.1 11010 0.075 kbit/s Rec. V.6 and X.1 11011 0.110 kbit/s Rec. V.6 and X.1 11100 0.150 kbit/s Rec. V.6 and X.1 11101 0.200 kbit/s Rec. V.6 and X.1 11110 0.300 kbit/s Rec. V.6 and X.1 11111 12 kbit/s Rec. V.6 and X.1 All 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) Figure 38/Q.763, p. - Intermediate rate indicator is coded: 00 not used 01 8 kbit/s 10 16 kbit/s 11 32 kbit/s - 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 sup- port 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 con- trol 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 net- work specific rules. 3) Octet 3b for Recommendation V.120 rate adaption | (see Figure 39/Q.763) Figure 39/Q.763, p. - 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 establish- ment 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 indica- tor 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 negotiation is done in-band using logical link zero l) User information layer 2 protocol identification 00010 Recommendation Q.921 (I.441) 00110 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 proto- col 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 C B: Service 1 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 B: Service 1 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 3.38 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 informa- tion field described in Recommendation Q.931, S 4.5.29. 4 ISDN user part messages and codes 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: - 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: F = mandatory fixed length parameter; V = mandatory variable length parameter; O = 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 indi- cated. 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 expli- citly in Tables 5/Q.763 to 28/Q.763. Tableau 5/Q.763 [T5.763], p. 28 Tableau 6/Q.763 [T6.763], p. 29 Tableau 7/Q.763 [T7.763], p. 30 Tableau 8/Q.763 [T8.763], p. 31 Tableau 9/Q.763 [T9.763], p. 32 Tableau 10/Q.763 [T10.763], p. 33 Tableau 11/Q.763 [T11.763], p. 34 Tableau 12/Q.763 [T12.763], p. 35 Tableau 13/Q.763 [T13.763], p. 36 Tableau 14/Q.763 [T14.763], p. 37 Tableau 15/Q.763 [T15.763], p. 38 Blanc Tableau 16/Q.763 [T16.763], p. 39 Blanc Tableau 17/Q.763 [T17.763], p. 40 Tableau 18/Q.763 [T18.763], p. 41 Tableau 19/Q.763 [T19.763], p. 42 Tableau 20/Q.763 [T20.763], p. 43 Tableau 21/Q.763 [T21.763], p. 44 Tableau 22/Q.763 [T22.763], p. 45 Tableau 23/Q.763 [T23.763], p. 46 Tableau 24/Q.763 [T24.763], p. 47 Tableau 25/Q.763 [T25.763], p. 48 Tableau 26/Q.763 [T26.763], p. 49 Tableau 27/Q.763 [T27.763], p. 50 Tableau 28/Q.763 [T28.763], p. 51 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 indi- cated 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 uninter- pretable 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 S 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. Tableau A-1/Q.763 [T29.763], p. Tableau A-2/Q.763 [T30.763], p. MONTAGE: REC. Q.764 SUR LE RESTE DE CETTE PAGE