[asterisk-users] Phantom Rings

[Brent Davidson]

Lee Jenkins wrote:
> Brent,
>
> I had a similar problem and I feel for you, its frustrating.
>
> Are you using polycom phones by chance?  Here is the problem that I had, not 
> sure if your problem is related.
>
> Specs:
>
> - 6 Polycom 301 phones.
> - CentOS 4 Server with Asterisk 1.2.x
> - Sangoma A200 card with 3 FXO ports.
>
> Pretty simple settings for a small office where a group ring between all 6 
> polycoms was initiated once the call was received.  After that it would go to a 
> auto attendant and give the caller option to continue to hold, leave a message, etc.
>
> At any rate, once in a while, Caller ID would fail, either on the Sangoma card 
> or somewhere in Asterisk, not sure, but CLI clearly showed an error on caller ID 
> every once in a while when a POTS call came in.
>
> All six polycoms would ring, but when you picked up the handset or hit the 
> Answer soft button, nothing would happen, you couldn't answer the call.  The 
> phones would just ring, and ring and ring for the duration of the group ring 
> (about 60) and the customer was really annoyed since it was a small office.
>
> Continuing, the problem finally turned out to be the polycoms!  When no caller 
> ID information was present, the polycoms wigged out and while they did ring, you 
> could not get the phones to pick up.
>
> I could readily replicate the behavior by initiating a Call File without 
> specifying the caller ID information using the local channel.  It would happen 
> every time.  Specifying the CID would allow the polycoms to work correctly.
>
> On the customer side, I did a quick GoToIf in their dialplan to see if the 
> caller id info was set and if it wasn't I would set it manually to something like:
>
> CALLERID(num)=555-555-5555
> CALLERID(name)=CID FAILURE
>
>
> That cleared up the problem.
>
> HIH
>
> --
> Warm Regards,
>
> Lee
>   
That really doesn't surprise me with Polycoms.  They have excellent 
voice quality but their interface is dismal.  I'm using Snom phones and 
I'm fairly certain the problem is with the phone line.  I have all 
callerID settings disabled as the Telco is unable to provide it along 
with our rollover line setup due to limitations in their antiquated 
switch.  The CLI and Logs all plainly show the calls as if they were 
normal calls with the exception of a message about "Failed to write 
frame" and no DTMF attempts, then the call is routed into the operator 
queue.  The calls always came in on Zap1-1 so I tried swapping the 2 
lines to see if it stayed on port 1 or if the phantom followed the 
line.  As expected, the phantom rings followed the line and began 
showing up on Zap2-1.  So it pretty has to be something in the telco, 
but I'm not sure what.  Putting "WaitForRing(3) before the "Answer" 
command in my IVR menu eliminates most of them, but sometimes more of 
them slip through.

-Brent