ADTRAN ISU 512e Manual page 119

Appendix B. Status Buffer Messages
FACILITY_NOT_SUB
The channel type requested has not been subscribed by the user.
FBW disconnected
BONDING negotiation failed due to a disconnect on a B-Channel.
Flash Failed
Writing to or erasing flash memory caused an error.
Hangup1/2
The call on either the first or second channel was disconnected by the
ISU. The far-end phone number is also displayed.
INCOMING_CALL_BA
Incoming call barred. The network will not allow an incoming call.
INCOMPATIBLE_DEST
The called number cannot accept the type of call that has been placed.
INTRWORKING _UNS
A message was sent by a far-end network that was not understood.
INVALID_CALL_REF
Call control error.
INVALID_ELEM_CON
Call control error.
61203086L1-1 ISU 512e User Manual B-7