Cause value 91

Last Updated : Oct 15, 2014 |
[0x5B/0xDB]

Invalid transit network selection

Cause

The call cannot be completed because the equipment that sends Cause value 91 receives a request to route a call to a disconnected transit network, or the transit network identification received is in an incorrect format. For the correct format of a number, see Annex C of the ITU Q.931 specification for TNS IE or NSF IE.

Communication Manager does not originate Cause value 91.

Proposed Solution

Procedure

  1. Check Communication Manager administration for the Cause value generated by the network.

    Communication Manager sends the transit network identification in the NSF IE instead of the TNS IE. The protocol version on the DS1 screen does not match the near-end ISDN network that is terminating the D-channel.

  2. You must contact the ISDN network service provider and try to line up the protocols used. NI-2 only supports the TNS IE, while custom protocol supports use of the NSF IE for this purpose.