Caller ID disappear with Enhanced Line mode

[notariannil1]

We were required to change any 88xx phones with more than 2 lines to ELM when our last network switch upgrade was completed. Phones would continuously cycle between registered and unregistered.  ELM solved the issue.  However, users complain because once the call is connected, the Caller ID disappears and the only way to see it is by selecting "..." then details.

Is there any way to keep the Caller ID on the screen during the conversation.  This is a request by our police department.

Thank you

[Jonathan Schulenberg]

Um, what?! Standard vs. enhanced line mode should have no impact on the phone’s ability to stay registered. I’d be focused on finding root cause of that so you can revert to standard.

[notariannil1]

https://community.cisco.com/t5/ip-telephony-and-phones/8851-phones-in-partial-registered-state/td-p/3010535

We had this issue and ELM helped resolve.  Maybe since I upgraded to 12.5 I can revert back to SLM. 

[Jonathan Schulenberg]

That thread is mostly talking about an expected behavior: if a phone has more DNs assigned to it than PLKs configured in the Line Button Template the excess/overflow can’t register, thus partially registered. The reply talking about KEMs misunderstood how to configure the Line Key Template; they needed to skip the physical button positions that aren’t functioning as a PLK in standard mode (eg buttons 6-10 on an 8841/51/61).

The other scenarios are most likely a bug. I’d  update firmware to one of the current 14.1+ train and see if standard mode works. If not, that may be worth a TAC case.

The odd part of your situation is the correlation with a switch upgrade. That makes me think there is a network issue somewhere, eg packet loss. It may be worth running a PCAP of a phone configured to span traffic southbound to the PC Port and look for TCP retransmissions. Perhaps there is a bad uplink connection on the new switch?