Trunks locking up on Sx2000 or 3300(with per cabinets)

[Northeaster]

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I have experienced this frequently on a SX2000 with analog (ground start) trunks in several per cabinets. I have heard that it also occurs on the 3300, with analog trunks (likely loop start) as well as with PRIs.

The problem likely occurs more often when a customer transfers a call outside the switch (using a 2nd trunk) and for some reason the trunks do not get release. The CO is DMS.

Besides checking for COD (Central Office Disconnect) / Disconnect Supervision at the CO (on the DMS), are there other things to check?

Normally we discourage customers from making outbound transfers. however, some times they insist (or have been told it will work by sales) so we have to put up with it.

In my experience, with the analog trunks, I would just put the butt set on each trunk, and if I heard dead air, pull the jumpers off, and you would always see two trunk lights go out. This is why I assume that it happens during outside transfers.

Any thoughts??
 
       

[Chakara]

  I had a similar problem with a client - although in our case it was resolved when we reversed tip/ring on the offending trunks.....

[ralph]

Old issue.
I've seen it a lot with analog extension lines.   What would happen is a user would do is call a number, hear a busy, hit hook switch, redial, hear a busy, hang up.   No a trunk has been transferred to another trunk listening to a busy.
I ended up restricting trunk to trunk transfers.   
BTW:  Never had this with PRI.   I think becuase of the the way PRI's work, this problem doesn't happen.

Play with the Circuit descriptor numbers.   You should be able to direct select a trunk, make an outbound call, have the far end hang up and you should see the call clear.  If you put your butt set on the line you may even hear the "click" of the disconnect signal.

Ralph

[v2win]

You could set up call duration limits on the trunks and set the timers for a couple of hours.

A scheduled reboot will also clear the trunks.