Refer to the exhibit.
Which three options are potential reasons the FXO port is not receiving Caller ID? (Choose three.)
A. “Enable Caller ID” was not configured on the Cisco Unified Communications Manager configuration.
B. The FXO port was configured to “loop-start” instead of “ground-start”.
C. The Timing Guard-out parameter is incorrectly set to 1500 ms.
D. “Connection polar opx immediate” was used and does support caller ID.
E. Gateway with IOS 12.4(24T) was used and does not support this feature.
F. The NTFY message contains a Hung Up parameter.
A,C maybe D if it is plar
Timing guard out – For Caller ID to work for FXO ports registered to a Cisco Unified CM, the range in milliseconds must be between 1000 to 2000.
CallerID on MGCP wth FXO was supported in 12.4(20) /CM 8
community.cisco.com:
https://community.cisco.com/t5/ip-telephony-and-phones/caller-id-display-problem/td-p/1516698
Just to complete the answer: Caller ID support with MGCP-controlled ports is supported but not until IOS 12.4(24)T and Communications Manager 8.0 or later.