sundance-communications.com/forum Forums TDM Business Telephone Systems Comdial Telephones & Systems Callers on hold disconnecting

Comdial DSU II - within the past couple of months callers on hold have been disconnecting - maybe two or three per week. No particular line or set of circumstances that we can nail down. Call rings in, is answered (doesn't matter where answered - however majority are answered at reception) - put on hold, intended is tracked down. During that time, line key will go out and call is not recoverable. Caller will call back. Live converstations are not disconnecting unexpectedly. No phone system changes or telco changes (of which we are aware). Hold release timer is set to default value (350ms if memory serves) on all lines.

Open to suggestions...
Thanks!
Mike

Weak loop current from the C.O.

1. Have you reset system??

2. What happens when you get on buttset on the line
and customer puts caller on hold??

3. I think hold release can be set to either 50ms
or 350ms. No in between. Might check that.

Good Luck

Will look at loop current...

Because this happens so infrequently - less than 1% of all calls put on hold drop - it's tough to catch it misbehaving. We did restart the KSU. Hold release is set to 350ms on all lines.

Thanks!
Mike

Since it's so infrequent, see if the customer can narrow it down to a specific line. If you go onsite, you should be able to test each line, by putting each on hold. If loop current is flakey, it might take the customer to keep track of which line(s) it happens on.

Have they asked the customer if they hung up to call back after being on hold for an extended period? Do they have MOH or just silence? Are those being cut off on VOIP or cell vs landline? As well as questions others have asked, you'll need your customers help to get to the bottom of this one.

Follow up:

1. Line current is 73ma on all lines - quite high from our perspective...maybe even high enough to have caused some equipment damage. We try installing current limiters and see if it makes a difference.

2. Per our request, customer has logged disconnects for the past month - results are what would be expected. Most disconnects on line 1, fewer on line 2, still fewer on line 3 etc. No discernable pattern.

3. Folks will call back and state that they were disconnected. Even though they don't have MOH, I don't think that the callers are giving up and disconnecting.

Mike

That current is high and I have seen damage from it.
Short of replacing the KSU ( it may be at fault), the only other thing you could look for is user error. By that I mean someone that does not have prime line or prime group and selects a blinking line key (not looking), does not hear dial tone and hangs up.
I know this is a stretch.

Try adding MOH? You will probably need a small
pre-amp to make it loud enough to hear

I am not trying to get too off track but I had an old AT&T merlin plus that would drop calls on hold. It ended up being plugged into the same circuit as a copier. We used a different outlet and it worked fine ever since, and is still working (9 years later).