SS7-ISUP, DSS1 Information Message

SS7-ISUP (30/Q.763 (09/97))

A message sent to convey information in association with a call, which may have been requested in an information request message.

ParameterTypeLength (octets)
Message typeF1 

Information indicators
        3.28
F
2
Calling party's category
        3.11
O
3
Calling party number (Note)
        3.10
O
4-?
Call reference
        3.8
O
7
Connection request
        3.17
O
7-9
Parameter compatibility information
        3.41
O
4-?
Network specific facility
        3.36
O
4-?
End of optional parameters
        3.20
O
1

NOTE - Peer-to-peer interworking with an earlier version of ISUP may result in format errors and lead to the release of the call.

DSS1 (3-10/Q.931)

This message is sent by the user or the network to provide additional information. It may be used to provide information for call establishment (e.g. overlap sending) or miscellaneous call-related information.

Information elementDirectionTypeLengthNote
Protocol discriminatorBothM1
Call referenceBothM2-*
Message typeBothM1
Sending completeBothO (Note 1)1
Causen->uO2-32
Displayn->uO min 2 octets, max. 34 or 82 octets
Keypad facilityu->nO2-34
Called party numberBothO2-* 

NOTES
1	This message has local significance, but may carry information of global significance.
2	This message may be sent with the dummy call reference defined in 4.3 when feature key management procedures are used (see Recommendation Q.932); otherwise the minimum length is 2 octets.
3	Included if the user optionally indicates completion of overlap sending to the network, or if the network optionally indicates completion of overlap receiving to the user.
4	Included if the network provides information that can be presented to the user.
6	Either the Called party number or the Keypad facility information element is included by the user to transfer called party number information to the network during overlap sending. The Keypad facility information element may also be included if the user
 wants to convey other call establishment information to the network, or to convey supplementary service information.
7	Included if the network optionally provides additional information describing tones.
8	Either the Called party number or the Keypad facility information element is included by the user to convey called party number information to the network during overlap sending. The Called party number information element is included by the network to
convey called party number information to the user during overlap receiving.