Intermittent call disconnects after one ring

[charlieg12]

Hi all,

Wondering if anyone else has come across this scenario as pulling my hair out trying to find a fix:

We are running CUCM 7.1.5 (7.1.5.32900-2), with inbound calls delivered via an ISDN-30 to a H323 gateway (2851 running 12.4-24.t4 spservices) calls match a translation pattern that points to a hunt pilot (3 phones in the line group) - the problem is that every couple of days at random periods, the calls disconnect after ringing once, similar to when codec mismatch happens.

I've run an isdn q931 debugging but this is showing the call disconnect code as 16 i.e normal call clearing, odd thing I have noticed is that when viewing the calls via a show call hist voice id .. I see no valid IP on the media i.e the below is what we see:

RemoteSignallingPort=1720

RemoteMediaIPAddress=0.0.0.0

The problem only affects calls into the hunt group/ pilot e.g calls to other DDI's/ internal extensions are ok during the period these calls disconnect, so I do not believe the ISDN circuit itself is at fault, nor with the gateway.

The problem only occurs for around 10 minutes and then normal service resumes, it only appears to be affecting this particular site (we have around 40 sites setup in a similar manner and no-one else has reported the issue).

Any help appreciated

Thanks,

[charlieg12]

Well after trying everything we could think of, including replacing all hardware on site TAC came back with the following:

CSCto78441 Bug Details

7962 phones are going off-hook and   then on-hook 400 milliseconds later

Symptom: 7962 phones are going off hook and then on hook 400 milliseconds later, which   prevents the user from answering the call properly. This behavior can be seen   in the SDI traces: 11:33:42.540 |StationInit: (0000030) OffHook.|1,100,49,1.584290 and then back on hook roughly 400 milliseconds later: 11:33:42.981 |StationInit: (0000030) OnHook.|1,100,49,1.584297 Conditions: So far, this has been seen in IP phones starting with serial numbers FCH1450   and up to FCH1504 Workaround: None at this time.

[shane.orr]

Charlie, did this end up solving your issue 100 percent.  I still seem to be plagued with issues even after replacing phones.  I was just curious.

Thanks in advance

Shane

[charlieg12]

Hi Shane,

In my case it did seem to be a batch of faulty hardware, I had the same issue at another site a couple of months later where one of the phones SN started with same characters

Have you been able to see the OffHook/ OnHook behaviour in your SDI traces?

[shane.orr]

Yes I do see the 400 millisecond behavior in the SDI traces. After further investigation it looks like my received RMA phones are also in the problematic serial number range. *sigh

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[charlieg12]

Replaced mine with 7965's as same thing happened first time I swapped them

[shane.orr]

Cool - thanks for taking time to reply and much appreciated!!

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[Ryan Marquart]

Did this issue get resolved?  We are having the problem where our inbound calls ring once, then nothing.  Seems to only happen to phones in a hunt group.  Running Call Manager 8.5

[shane.orr]

I would start by looking at the CDR to see what the disconnect cause code is.  That will be your first clue.  Then looking further into the SDI logs, if you see a normal disconnect cause code and around a 400 millisecond disconnect time like referenced above, then you are probably hitting the phone bug that we were.  This bug would cause the issue on both direct calls and calls to a hunt group because the phone would accidentally answer and hang up the call on its own.  One thing you can do is see if your serial number ranges are listed above too.  We ended up replacing a bunch of phones twice because the first time we got the same S/N range before our problem finally subsided.

Otherwise you might be experiencing something different.

[MM]

I realize this thread is old, but I wanted to reply since I found the information about the Bug to be helpful. I was having this same problem, I had 4 phones with a shared line appearance. I would call and the line would ring for a half a ring and then disconnect. The short term fix for me was to take each receiver and go off hook and then on hook again, once I did that for all of the phones that extension appeared on the extension would ring in again normally. 

I know this isn't an ideal situation but will help until you replace the hardware.