Hopefully someone has some ideas. Our Comdial DXP system w/about 55 phones randomly locks or freaks out. We have about 55 phones, all pots lines (no PRI or T1), and the newer Keyvoice VM w/CTI server.

When the problems occur, the lights/displays on the phones will stay locked in their current state, people who pick up the phone will not get a dial tone, but calls that were already in progress will stay that way. Serial console on the server card will stay active, and nothing shows up wrong in the status logs. Once the problem occurs, the wide open office and keyvoice lose serial connectivity (they use a serial card on the AUX board). The only way to fix it is to power the system down and back up.

Our phone people have replaced the system ram, and suggested I look for bad phones with the intercom light blinking, or to watch for error lights on the system boards. I've seen them in the past but replaced them all. Just about all our phones are 8024S's, most of which are 10 years old.

I've watched for error lights on the system boards, ran around and checked phones I suspected to be the problem, and constantly check status logs. Today a user reported a buzzing sound and their call being dropped - and of course, the system locked for a minute and came back to life on its own. Serial ports weren't working as usual after that.

I'm suspecting the system power supply due to the buzzing symptom, but my phone people don't seem to think there's any problems with it (I've yet to see them even so much as bring in a meter and check it). I do believe it could be 1-2 bad phones too but if so they're impossible to find!! We are in the insurance biz and phones are extremely critical to us. Anyone have any clues as to why our system would act up like this?!

Thanks in advance,

Jeff G
Langhorne, PA

First thing I would check is the ground to the system. It should be 10 awg. and connected to a good earth ground.
mark

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Reliable Telephone Service

Grounds are all connected pretty good - system worked flawless for a long time before this started happening.

Go back to what Mark say about the ground.
The DXP is very sensitive to ground potential changes. The ground should be an electrical/building ground. Not a water pipe ground. Pluming gets a mix of pipe today, some conductive and some not. I have seen a DXP go into trouble everytime someone used a sink or toilet in one location. Have you had any elecrical or pluming changes just prior to this problem?

[This message has been edited by CMDL_GUY (edited April 26, 2005).]

Hmm...I'll have to check with the building manager. We're on the top floor of a 4 story building so anything's possible. I'll let you know.

Thanks for your help so far, this has been really frustrating.

Jeff

On the 4th floor...
I bet that you are grounded to the plumbing and someone swapped in some PVC and blew your ground connection.

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Avaya Telephone Repair
Comdial Telephone Repair

[This message has been edited by paul144 (edited April 27, 2005).]

Ok I checked the grounds.

Starting with the outlet, there's a power filter directly on that on which the Comdial is plugged into. Testing the ground pin from that outlet to another one on another wall showed the ground is connected properly. I also checked for continuity between the cabinet and the ground and there's a good connection there - 0 ohms.

On the wiring end, there's a decently heavy green ground wire connecting to both cabinets and the incoming line fuse/surge blocks, and that then runs up into the ceiling where it connects to a hook where a lot of the wiring runs through, then up again and bolts to one of the steel roof rafters. I think its safe to say the grounds are connected well.

I've been working here for almost 7 years now and for the first few years the system had been trouble free. The only major change I can think of was adding a 4 port serial card to the AUX board, and switching the old voicemail system to the newer CTI based voicemail system. I don't remember if these problems started before that or not though.

I did at one point find a junction in one of the serial lines that ran to another phone jack (that an old modem was still plugged into!). I fixed that and figured that was the problem but its still happening. It comes and goes...it may work great for 2-3 months, then the problems may occur 2-3 times in a 5 day period, then wait another few months before happening again. Its really frustrating!

Anyways, thanks for the help so far, any new ideas just let me know!

Jeff

Forgot to mention that between the power filter and the cabinet is an APC 1400va UPS thats pretty new. When I installed that I disconnected the Comdial battery box since the batteries are shot and useless anyway.

yank the plug on that battery back up and see if the system goes goofy. I've seen them fail by dropping voltage too low before they shut down or regain the power. Did you check the ground for transient voltage?
mark


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Reliable Telephone Service

Check the output of the APC with a scope and see if you have a nice clean sine wave. The DXP doesn't like square wave output at all.

Well normally IT guys don't carry around scopes but I do have one, unfortunately I just don't have a probe for it right now. Once I pick one up I'll check it out and let you know.

I was thinking about the last post and in fact our power blipped yesterday, and about 2 hours later the system did fail. Now I'm hoping the power blips again so I can see if its consistent! When I say blip - I mean the lights flicker for a split second, just enough to make the relays click on the UPSes.

Thanks,

Jeff

Well as an update, we've since replaced almost everything in the system, but I found 1 or 2 of the wires going to the VM serial port to be disconnected. When I hooked my laptop up to the serial port I couldn't even get a login screen (was all garbage), I have no idea how it ever worked to begin with.

It may have been one of the other boards or something too, but so far we've had no locks! The serial port was wired very poorly, and I've since redone it and all is well!
*knock on wood*