Figure 26/Q.763 - CCITT 73380

	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 - CCITT 73380

	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)	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 h).
Figure 28/Q.763 - T1110060-88

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 - CCITT 73360

	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.
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).
3.29	Redirection information
	The format of the redirection information parameter field is shown in Figure 30/Q.763.
Figure 30/Q.763 - CCITT 73375

	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 redirection information presentation restricted
0	1	1	call forwarded
1	0	0	call forwarded, all redirection 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:	Original redirection reasons
0	0	0	0	unknown/not available
0	0	0	1	user busy
0	0	1	0	no reply
0	0	1	1	unconditional
0	1	0	0	ü
  to				ý	spare
1	1	1	1	þ
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 available
0	0	0	1	user busy
0	0	1	0	no reply
0	0	1	1	unconditional
0	1	0	0	ü
  to				ý	spare
1	1	1	1	þ
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:
a)	Odd/even indicator: see § 3.7 a)
b)	Nature of address indicator: see § 3.7 b)
c)	Internal nerwork number indicator: see § 3.7 c)
d)	Numbering plan indicator: see § 3.7 d)
e)	Address signal: see § 3.8 f)
f)	Filler: see § 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 - CCITT 85270

	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 - CCITT 73331

	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 - CCITT 73370

	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 - T1110120-88

	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.
Figure 35/Q.763 - CCITT 73380

	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	ü
 to			ý	spare
11111111	þ
	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 - T1101560-89

	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

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 × 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	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 × 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 bidirectional 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 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	Recommendation G.711 m–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 § 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 - T1121570-89

–	The synchronous/asynchronous indicator is coded:
0	synchronous
1	asynchronous
Octets 3b to 3d may be omitted 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 - T112580-89

–	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 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)
Figure 39/Q.763 - T1110150-88

–	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	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 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 - CCITT 73370

	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 - T1110150-88

	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.
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 of 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 of the parameter. The value in the table includes:
–	for type F parameters the length, in octets, of the parameter content;
–	for type V parameters the length, in octets, of the length indicator and of the parameter content. The minimum and the maximum length are indicated;
–	for type O parameters the 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.

TABLE 5/Q.763
Message type:	Address complete
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Backward call indicators	 3.4 	 F	 2	
 Optional backward call indicators	 3.24	 O	 3	
 Cause indicators	 3.10	 O	 4–?	
 Connected number	 3.14	 O	 4–12	
 Call reference	 3.6	 O	 7	
 User–to–user indicators	 3.37	 O	 3	
 User–to–user information	 3.38	 O	 3–131 a)	
 Access transport	 3.2	 O	 3–?	
 End of optional parameters	 3.17	 O	 1	
 a) Some networks may only support up to 35 octets.

TABLE 6/Q.763
Message type:	Answer
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Backward call indicators	 3.4 	 O	 4	
 Optional backward call indicators	 3.24	 O	 3	
 Call reference	 3.6 	 O	 7	
 User–to–user indicators	 3.37	 O	 3	
 User–to–user information	 3.38	 O	 3–131 a)	
Connected number	 3.14	 O	 4–12	
 Access transport	 3.2	 O	 3–?	
 End of optional parameters	 3.17	 O	 1	
 a) Some networks may only support up to 35 octets.

TABLE 7/Q.763
Message type:	Call progress
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Event information	 3.18	 F	 1	
 Cause indicators	 3.10	 O	 4–?	
 Call reference	 3.6 	 O	 7	
 Backward call indicators	 3.4 	 O	 4	
 Optional backward call indicators	 3.24	 O	 3	
 Access transport	 3.2 	 O	 3–?	
 User–to–user indicators	 3.37	 O	 3	
 User–to–user information	 3.38	 O	 3–131 a)	
 Redirection number	 3.30	 O	 5–12	
 End of optional parameters	 3.17	 O	 1	
 a) Some networks may only support up to 35 octets.

TABLE 8/Q.763
Message type:	Circuit group query response
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Range and status a)	 3.27	 V	 2	
 Circuit state indicator	 3.12	 V	 3–33	
 a) The status subfield is not present.

TABLE 9/Q.763
Message type:	Circuit group reset acknowledgement
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Range and status	 3.27	 V	 3–34	

TABLE 10/Q.763
Message type:	Confusion
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Cause indicators	 3.10	 V	 3–?	
 End of optional parameters	 3.17	 O	 1	

TABLE 11/Q.763
Message type:	Connect
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Backward call indicators	 3.4 	 F	 2	
 Optional backward call indicators	 3.24	 O	 3	
 Connected number	 3.14	 O	 4–12	
 Call reference	 3.6 	 O	 7	
 User–to–user indicators	 3.37	 O	 3	
 User–to–user information	 3.38	 O	 3–131 a)	
 Access transport	 3.2	 O	 3–?	
 End of optional parameters	 3.17	 O	 1	
 a) Some networks may only support up to 35 octets.

TABLE 12/Q.763
Message type:	Continuity
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Continuity indicators	 3.16	 F	 1	

TABLE 13/Q.763
Message type:	Facility reject
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Facility indicator	 3.19	 F	 1	
 Cause indicators	 3.10	 V	 3–?	
 User–to–user indicators	 3.37	 O	 3	
 Call reference	 3.6 	 O	 7	
 End of optional parameters	 3.17	 O	 1	

TABLE 14/Q.763
Message type:	Information
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Information indicators	 3.21	 F	 2	
 Calling party's category	 3.9 	 O	 3	
 Calling party number	 3.8 	 O	 5–12	
 Call reference	 3.6 	 O	 7	
 Connection request	 3.15	 O	 7–9	
 Access transport	 3.2 	 O	 4–?	
 End of optional parameters	 3.17	 O	 1	

TABLE 15/Q.763
Message type:	Information request
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Information request indicators	 3.22	 F	 2	
 Call reference	 3.6 	 O	 7	
 End of optional parameters	 3.17	 O	 1	

TABLE 16/Q.763
Message type:	Initial address
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Nature of connection indicators	 3.23	 F	 1	
 Forward call indicators	 3.20	 F	 2	
 Calling party's category	 3.9 	 F	 1	
 Transmission medium requirement	 3.35	 F	 1	
 Called party number	 3.7 	 V	 4–11	
 Transit network selection a)	 3.34	 O	 4–?	
 Call reference	 3.6 	 O	 7	
 Calling party number	 3.8 	 O	 4–12	
 Optional forward call indicators	 3.25	 O	 3	
 Redirecting number	 3.28	 O	 4–12	
 Redirection information	 3.29	 O	 3–4	
 Closed user group interlock code	 3.13	 O	 6	
 Connection request	 3.15	 O	 7–9	
 Original called number	 3.26	 O	 4–12	
 User–to–user information b)	 3.38	 O	 3–131	
 Access transport	 3.2 	 O	 3–?	
 User service information c)	 3.36	 O	 4–13	
 User–to–user indicators	 3.37	 O	 3	
 End of optional parameters	 3.17	 O	 1	
 a)	For national use only.
b)	Some networks may only support up to 35 octets.
c)	This parameter can be repeated in case of an alternate bearer service, in which case the initial parameter represents the initial establishment mode.

TABLE 17/Q.763
Message type:	Release
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Cause indicators	 3.10	 V	 3–?	
 Redirection information	 3.29	 O	 3–4	
 Redirection number	 3.30	 O	 5–12	
 Signalling point code a)	 3.31	 O	 4	
 Access transport	 3.2 	 O	 3–?	
 User–to–user information b)	 3.38	 O	 3–131	
 Automatic congestion level	 3.3 	 O	 3	
 End of optional parameters	 3.17	 O	 1	
 a)	For national use only.
b)	Some networks may only support up to 35 octets.

TABLE 18/Q.763
Message type:	Release complete
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Cause indicators	 3.10	 O	 5–?	
 End of optional parameters	 3.17	 O	 1	

TABLE 19/Q.763
Message type:	Subsequent address
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Subsequent number	 3.32	 V	 3–10	
 End of optional parameters	 3.17	 O	 1	

TABLE 20/Q.763
Message type:	User–to–user information
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 User–to–user information	 3.38	 V	 2–130	
 Access transport	 3.2 	 O	 3–?	
 Call reference	 3.6 	 O	 7	
 End of optional parameters	 3.17	 O	 1	

TABLE 21/Q.763
Message type:	Delayed release (national use)
		Forward transfer
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Call reference	 3.6 	 O	 7	
 End of optional parameters	 3.17	 O	 1	

TABLE 22/Q.763
Message type:	Suspend
		Resume
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Suspend/Resume indicators	 3.33	 F	 1	
 Call reference	 3.6 	 O	 7	
 End of optional parameters	 3.17	 O	 1	

TABLE 23/Q.763
Message type:	Blocking
		Blocking acknowledgement
		Continuity check request
		Loop back acknowledgement (national use)
		Overload (national use)
		Reset circuit
		Unblocking
		Unblocking acknowledgement
		Unequipped circuit identification code (national use)
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	

TABLE 24/Q.763
Message type:	Call modification completed
		Call modification request
		Call modification reject
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Call modification indicators	 3.5 	 F	 1	
 Call reference	 3.6 	 O	 7	
 User–to–user information	 3.38	 O	 3–131 a)	
 End of optional parameters	 3.17	 O	 1	
 a) Some networks may only support up to 35 octets.

TABLE 25/Q.763
Message type:	Circuit group blocking
		Circuit group blocking acknowledgement
		Circuit group unblocking
		Circuit group unblocking acknowledgement
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Circuit group supervision message type indicator	 3.11	 F	 1	
 Range and status	 3.27	 V	 3–34	

TABLE 26/Q.763
Message type:	Circuit group reset
		Circuit group query
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Range and status a)	 3.27	 V	 2	
 a) The status subfield is not present.

TABLE 27/Q.763
Message type:	Facility accepted
		Facility request a)
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type	 2.1 	 F	 1	
 Facility indicator	 3.19	 F	 1	
 User–to–user indicators	 3.37	 O	 3	
 Call reference	 3.6 	 O	 7	
 End of optional parameters	 3.17	 O	 1	
 a)	Whether or not the facility request message should contain a connection request parameter requires further study.

TABLE 28/Q.763
Message type:	Pass–along
Parameter	 Reference (§)	 Type	 Length (octets)	
 Message type (00101000)	 2.1 	 F	 1	
 Message type
 Mandatory fixed part
 Mandatory variable part
 Optional part	
 Any message in Tables 5/Q.764 to 27/Q.764 which is relevant only at the “endpoint” of a connection as defined in § 3 of Recommendation Q.764			

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.

TABLE A–1/Q.763
Fields and their default interpretations
Field name with unrecognized code	 Default interpretation	
 Charge indicator	 Charge	
 Called party's status indicator	 No indication	
 Called party's category indicator	 No indication	
 Calling party category	 Handle as an ordinary call	
 Address presentation restricted indicator	 Presentation restricted	
 Cause indicator–location	 (see note)	
 Cause value (unextended)	 Unspecified: within class xxx	
 Cause value (extended)	 Unspecified: interworking class	
 Calling party number response indicator	 Calling party number included	
 Connected number response indicator	 Connected number included	
 Redirecting number response indicator	 Redirecting number included	
 Satellite indicator	 Two satellites	
 Continuity check indicator	 Continuity check not required	
 Redirecting reason indicator	 Unknown/unavailable	
 Redirection counter	 Maximum redirections	
 Original redirection reason indicator	 Unknown/unavailable	
 Redirecting indicator	 Call forwarded, all redirection information presentation restricted	
 Closed user group indicator	 Non–CUG call	
 User–to–user (service 1)	 No information	
 User–to–user (service 2)	 No information	
 User–to–user (service 3)	 No information	
 Note – If a network receives an unrecognized location field from other networks, the default interpretation of this field will be the location of the network which sends the unrecognized location, otherwise the default interpretation is “beyond an interworking point”.

TABLE A–2/Q.763
Fields with no default interpretations
Uninterpretable field	
 Nature of address	
 Numbering plan	
 Address signal	
 Cause indicator–coding standard a)	
 Cause indicator–recommendation a)	
 Diagnostic	
 User service information (any field)	
 Transmission medium requirement	
 Call modification indicator	
 Event indicator	
 Facility indicator	
 Circuit state indicator	
 Automatic congestion level	
 Circuit group supervision message type	
 a)	Cause value interpreted as if coded “unspecified: interworking class” (1111111) and the location field interpreted as if coded “Beyond Interworking Point” (1010).