7861 SIP phone swaps calls on new inbound (bumps original caller to hold)

[james.irwin]

This is the description of the issue, which occurs occassionaly:

• User was talking on one of their lines mid-sentence and all of a sudden they were talking to someone else
• Each time the second caller they ended up with was a new caller; not someone on hold and not someone talking to another associate
• All occurrences coincided with new calls inbound
• No recollection of which line they started with or ended with
• One user did observe that the CallerID changed with her new caller
• Users had clear view of the phone; they did not push any buttons and nobody else touched their phone
• The original caller who gets bumped ends up on hold and another user can pick it up and continuing the conversation
• There were no phones with any other issues

Cluster/phone info

• 7861 phones running SIP
• CUCM version: 9.1.2.10000-28
• Phone Load:  sip78xx.2-2-3-4

Phone set up is as follows:

• 5 Lines set up on each phone
• 10 phones in store; all have exact same set up with shared line appearances
• Each line set for max call =1, roll over to next line if busy
• All calls inbound are a Hunt Pilot with the lines in the HL in order top down

Additional info:

• There are 30 stores, each set up the same way, each with their own Pilot, HL, etc
• Only one store is reporting the issue
• Stores have a mix of 7861 (SIP) and 6961 (SCCP) phones
• We do not have any log files that support the issue and we do not have Sniffer traces (yet)

Initial conclusions:

1. As other locations are set up 'cookie-cutter', is the issue truly at the one location?  If so, could it be a Layer2/Layer3 issue?
2. Parsing CUCM configs of device, line, pilot, HL, HG did not show any differences with setup; but I could have missed something.
3. The phones themselves (or at least one phone) is defective.
4. End user error

If you have any thoughts, please share them - this is truly a mystery to me!

Thank you

[markbatts · Accepted solution]

Hi James, this is my take on it  , though it is a very strange issue.

Based on you're initial conclusions.

1.In my opinion to get a call to move from active to on hold and then take a new call is not going to because by any layer2/3 network issue, so i would rule that one out.

2.There is no config i know that would create the issue you are having so again i would rule out a config error / difference.

3.Interesting one this , given that this only occurs at this site this would be the obvious conclusion however strange the issue.I have seen weird things in the past with new phones having sticky keys i.e getting stuck down.

4.Again this could be the obvious one , but again its a strange issue and would involve multiple key presses , so i doubt this one aswell.

To summarise i would go with the sticky keys option first , i.e maybe swop a few phones or at least ask the user to press all the buttons on the phone repeatedly to free them up.

[james.irwin]

I sent a request to the customer to replace the phone the same I day I posted the original thread.  As of this update, that was 11 days ago.  Customer did not replace phone and has not reported the issue again.  I believe Markbatts was right; stuck buttons or similar physical phone issue.