sundance-communications.com/forum Forums TDM Business Telephone Systems Samsung Telephones & Systems PRI Destabilizing OS7400 ?

Our site with 3-Cab 7400 is otherwise stable - latest software on all cards. Today the LCP's started resetting and finally the MP40 restarted. There were lots of PRI-related errors logged. The telco tech was on site and said his lines were clear and the fault was on our side (the usual story). My question is: To what extent can a PRI line destabilize the PBX?

I believe it can trigger a watchdog reset. Do you have an Adtran ACE or other CSU between the 7400 and the network interface?

I have a local 7200 customer that kept on having the same kind of problem and he found out just a couple weeks ago that it was his 10/100 switch.

When he replaced it with a new gigabit switch the alarms and resetting stopped.

I can't tell you for sure this is your problem, but they did everything under the sun and finally when they upgraded the switch to a new HP gigabit, ALL the previous problems stopped.

Its not easy to pinpoint some of the weird problems.

Thanks Guys.

First; There is no CSU and this is not spec'd in our country, so news to me.

I just found an old thread useful reading https://www.sundance-communications.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=17;t=000068;p=0&r=actu

To reply to Bunnie; Curiously there was a LAN problem around the same time the PRI went haywire and IT were running around trying to find the LAN point (Its a big campus). I wonder...

I am no IT guru, but we sold the 7200 to a company with a real, true, certified gizmo specialized IT guy. They had problems with voip phones and increased bandwidth and upgraded software swapped out battery backup units and the 10/100 was the last piece of hardware.

They had resets and I sent all the screen shots to our wonderful guru Ross at Pyramid and he couldn't see any bad Samsung hardware issue. Swapping out the old 10/100 for an HP gigabit stopped the problems cold. As much as I hate to point the finger, and as little as I would know how to pinpoint a bad switch, I would certainly advise the IT people to work with you.

I've had my fights with Samsung over the years, but everything that goes wrong is not their fault.

The CSU is a BIG help as it shows a NET loss or and EQUIP lost but it also possible you can have some problem in the PRi and it will not show a NET loss as it sees the circuit. It can also do error reporting. I wouldn't put in a T-1 or PRi without one.

Thanks, Bunnie

I second the Bunnie,
We have a customer with a 7400 and PRI. I was getting errors about once a day for two month's. The cards and system were not resetting but there were complaints of dropped calls and intermittent two way audio issue's. The VM was not seeing the disconnect from the Telco's PRI and there were random ghost calls to the receptionist. She would pickup and no one was there.

I installed an Adtran ACE and no lie I haven't had an error since and the issue's disappeared.

I won't install a PRI without one from now on.

In the US, it is legally required to have a CSU but no one checks and no one gets charged with a crime for not having one.

It is much more of a tool for the installer and the reason it is legally required is that it will prevent any damaging electrical current from the phone system flowing into the public network. That was more of an issue years ago than it is now.

Thanks, Bunnie

"It is much more of a tool for the installer and the reason it is legally required is that it will prevent any damaging electrical current from the phone system flowing into the public network."
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Yeah, but for me at least, more than once the CSU died protecting CPE from TELCO!

OK Thanks, I take your point on the CSU and will cetainly investigate that further.

But this problem seems to be more curious; today after a completely error free weekend, there was a Watchdog MCP restart. Around that time the LAN went down. I should mention that this is a hybrid system with no IP phones at all. We connect to the LAN for SMDR and OS Operator(s) and remote access.

How can the LAN bring down the PBX? Vice versa makes a little more sense to me. I do not think the PRI is bringing the PBX / LAN down ?!

Any chance you are using a dynamic PRI that shares bandwidth with broadband for internet access? Maybe a new provider that had 1 great deal, only he 'forgot' to tell you that the 'sharing' was going to happen and 'might' cause problems? And what happens if the network that you move SMDR information on goes down. Can this cause phone system problems? I know that Mitel systems, as an example, can be arranged to block outgoing calls if the SMDR storage area fills up!