Inbound Calls Interrupt Outbound calls on 8841 phones

[gmgarrian]

Hello,

I have a department with 10 users all using 8841 phones.  Line 1 is unique to the phone and line 2 is a shared line.  My issue if a user goes off-hook and starts dialing a number when an inbound call to that phone on either line arrives, the call in mid dial fails with the message "Call cannot be completed as dialed." Is does not matter if the active line making the call is the shared line or not. Phones: Cisco 8841 sip88xx.12-7-1-0001-393 max calls 6 busy trigger 4.

Tested with a 7906 SCCP11.9-4-2SR3-1S Issue did not occur, 7906 was able to complete the call without interruption.

I also have another department with a similar setup using 8851 phones, same firmware, sip88xx.12-7-1-0001-393, who is reporting they are not having this issue.

I am not seeing any configuration different between the phones that get interrupted calls and those that don't.

CUCM version is 11.5 (project in progress to upgrade to 15).

Has anyone run into this before? 

Thanks!

[Jerrytech1]

I see this on my 8851. So far hitting Decline is the only work around. I'll post if I find anything else.

[Mohammadreza Hadi]

set "Busy Trigger" to "1"
then when you are at dialing number, if anyone calls you, they will get busy tone, and will not interrupt you..

[gmgarrian]

Thanks for the suggestion...I'll give it a try.  

[gmgarrian]

This is not work.  Outbound calling is still interrupted.

[SteveK066]

I found that if a second line rings on an 8841, I can't make an outgoing call at all. If I press the prime line first and go off hook or then press speaker, I answer the call. Same thing happens even if I press Ignore while the 2nd line is ringing. I wonder, how is the customer selecting another line to make an outgoing call? 

Update - If I press the handset icon on the key directly across from my line key, I get dial tone and can make a call while the 2nd line is ringing. But, I have a custom soft key template, maybe that's why. 

[gmgarrian · Accepted solution]

TAC has assisted in finding a solution.  On the IP Phone configuration page, I changed the "Actionable Incoming Call Alert" setting to "Disabled."  After resetting the phone, outbound calls no longer get interrupted by incoming calls, and the issue is resolved.