| Parameter | Type | Length (octets) | Notes |
|---|---|---|---|
| Message type | F | 1 | |
| Backward call indicators | F | 2 | |
| Optional backward call indicators | O | 3 | |
| Backward GVNS | O | 3-? | |
| Connected number | O | 4-? | |
| Call reference | O | 7 | |
| User-to-user indicators | O | 3 | |
| User-to-user information | O | 3-131 | |
| Access transport | O | 3-? | |
| Network specific facility | O | 4-? | |
| Generic notification indicator | O | 3 | |
| Remote operations | O | 8-? | |
| Transmission medium used | O | 3 | |
| Echo control information | O | 3 | |
| Access delivery information | O | 3 | |
| Call history information | O | 4 | |
| Parameter compatibility information | O | 4-? | |
| Service activation | O | 3-? | |
| Generic number | O | 5-? |
NOTE 1 - This parameter may be repeated. NOTE 2 - Peer-to-peer interworking with an earlier version of ISUP may result in format errors and lead to the release of the call. |
| Redirection number restriction indicator | O | 3 | |
| Conference treatment indicators | O | 3-? | |
| End of optional parameters | O | 1 |