How can you tell if a call is being call forwarded? Well, you walk over to the phone and look for yourself it someone has set it that way. However, if that is not an option, like if you are at a remote site and you are not getting ANY cooperation from the users, then you can use the 'debug isdn q931' command in y our UC500 or your CME. See below and notice the three highlighted areas. You know its call forwarded when you see the "redirecting number". Interesting.
3741968: Nov 19 09:51:10.669: ISDN Se0/2/0:23 Q931: TX -> SETUP pd = 8 callref = 0x02C8
Bearer Capability i = 0x8090A2
Standard = CCITT
Transfer Capability = Speech
Transfer Mode = Circuit
Transfer Rate = 64 kbit/s
Channel ID i = 0xA9838E
Exclusive, Channel 14
Calling Party Number i = 0x80, '210'
Plan:Unknown, Type:Unknown
Called Party Number i = 0xA1, '2055552405'
Plan:ISDN, Type:National
Redirecting Number i = 0x00008F, '1007'
Plan:Unknown, Type:Unknown
3741969: Nov 19 09:51:10.705: ISDN Se0/2/0:23 Q931: RX <- CALL_PROC pd = 8 callref = 0x82C8
Channel ID i = 0xA9838E
Exclusive, Channel 14
3741970: Nov 19 09:51:12.621: ISDN Se0/2/0:23 Q931: RX <- ALERTING pd = 8 callref = 0x82C8
Progress Ind i = 0x8188 - In-band info or appropriate now available
