Dropped Calls When Incoming

We have a user (ext. 213) that will be on a call with someone, when another call comes in and goes into a ring group that ext 213 is either a part of, or is the voicemail to go to when the call is unanswered, as soon as someone picks up the call the initial call on 213 is dropped. in the log I show “span 1 got hangup request cause 16”.

Anybody have an idea what might be causing this to happen?

ISDN cause code 16 is defined as:

Cause No. 16 - normal call clearing.
This cause indicates that the call is being cleared because one of the users involved in the call has requested that the call be cleared.
What it means:
This could be almost anything; it is the vaguest of the cause codes. The call comes down normally, but the reasons for it could be:

  1. Bad username or password
  2. Router’s settings do not match what is expected by the remote end.
  3. Telephone line problems.
  4. Hung session on remote end.

So I would think the call is clearing on the PRI maybe because of some issue from the phone back to the PBX and hence the PRI? Thats my first thought.


Thanks for the response. Supposedly this happens quite a bit. I’ve requested them to send me time/date and phone number of calls that are getting dropped so I can try and find a rhyme or reason to it.

I would definitely compare logs and do some debugging on your side. It can be painful to try to have the telco admit it is something on their side (SIP, POTS or PRI). It could be something on your side too. I would increase the verbosity in asterisk, turn on some debugging and see if you can catch it real time. If not look in the logs with the increased verbosity.


It appears the issue may have just worked itself out. I touched base with them the other day and they said things have been fine. I guess if it does wind up happening again I’ll have to check all the logs. Lucky for me they are really good about giving me specifics in terms of time of call, phone number, and extension that picked up the call. makes trolling through the logs a lot easier!