When the first line on a Cisco 7960 or a 7940 series IP phone has an incoming call established, and if there is another incoming call on the second line, the Caller ID information for the second line is not displayed. This is observed after upgrading the Cisco CallManager to version 3.2.3 from 3.2.2c. The Caller ID is also displayed for the second line with Cisco CallManager version 3.2.2c.
A tone indicates the incoming call on the second line, but there is no display of the Caller ID. Call Forwarding On Busy (CFB) is configured for the second line and Call Forwarding on No Answer (CFNA) is configured to the voice mail.
This issue occurs when the Call Waiting is set to OFF, and the Cisco CallManager is version 3.2 or earlier, and the incoming call is forwarded to the next line to the same device.
To address this issue found in the Cisco CallManager 3.2, refer to these Cisco Bug IDs:
CSCdu37305: No Caller ID and notification in the second line
CSCdw26479: CLID not showing up on 794x/6x when cfwd to the same device
CSCdx14064: Calling party number not presented in status line on IP phone
With Cisco CallManager 3.2, the Caller ID information is shown only one line at a time. If there is an active call on line one (with Caller ID being shown), and another call comes in to line two, the focus stays with line one. To see the calls and Caller ID on line two, press i, followed by the line 2 button. In Cisco CallManager 3.3(3), the Caller ID for the second line will be visible in the front.
Installing the service release 3.2.3SR1 displays the CallerID above the Softkeys at the bottom. However, the Caller ID will not show up on the line instance.
For complete resolution of the issue, upgrade the Cisco CallManager to version 3.3(3), which has the feature that displays the Caller ID of any line on the corresponding line instance.