VTC ISDN Intermittent Outbound Dialing Issue

[Switchlady1]

We have ISDN lines for video conferencing (VTC) and the group that manages the VTC equipment complains about an intermittent problem with dialing outbound (internal and external). They are able to always receive inbound calls but on occasion, cannot connect when dialing outbound. The ISDN services is through our PBX, which uses PRI trunks for outbound calling. No other users on regular phones complains about an occasional outbound calling problem, only VTC folks. The complaint is that they see the call being dialed on the monitor but it sometimes doesn't connect and just immediately drops the call before establishing any connection. I don't know anything about their VTC equipment but both Tanberg and Adtran devices are being used separately and in different VTC rooms and on separate ISDN lines. When the problem occurs, the claim is that it happens on all of their VTC systems. The only common denominator is that they are all ISDN lines programmed through the switch. Again, this is an intermittent issue that seems to "fix" itself. It's working now but didn't work earlier this week so I'm pulling my hair out on this one! Anyone knows anything about what I've described? Oh yeah, their ISDN services are on different cards (one SILC and the other UILC card). I still think it's something with their equipment but trying to do all I can do to troubleshoot on the PBX side.

 

[SYQUEST]

You never mentioned what PBX switch you are using, or what kind of ISDN connections exist between the VTC and the PBX switch.
• Does the PBX have any alarm or error reporting?
• Any diagnostic capabilities?
• Does the VTC have any troubleshooting tools?
Those would be a good place to start. Do you have and test equipment like a T-Berd with ISDN options?

....JIM....

 

[Switchlady1]

SYQUEST,
Thanks for your response. I'm not very hardware literate nor do I have much experience with ISDN circuits, so forgive me if I'm not very helpful with my answers to your questions. We probably will have to contact our vendor to look at this closer as I may not be able to test at the level in which you've described.
- PBX switch: Option 81
- Kind of ISDN connections between the VTC and the PBX switch: I only know of one kind, BRI. If that's not what you're looking for, please let me know where to look to find out.
- Does the PBX have any alarm or error reporting?: Our switch is always spitting out stuff, so it's really hard to see specific error pertaining to this issue. The next time it happens I'll be on the lookout for error codes.
- Any diagnostic capabilities? NO
- Does the VTC have any troubleshooting tools? NO
- Do you have and test equipment like a T-Berd with ISDN options? Not me, but have access to one but the owner would have to assist.

 

[SYQUEST]

Those are some of the answers I needed. The Opt81 does have the reporting as you mentioned, but being fluent in the NT switch is important in order to find the info to troubleshoot it. The same goes for the testing tools which the Opt81 is known. Anyway, you will want to get your support person involved to login and read, etc. the logs and can test the BRI interfaces to find the problem. you might also have the person provide a little training to be more familiar with the switch. The NT Opt.81 is still one of the most versatile PBX switches ever made.

Hope this helps!
....JIM....

 

[Switchlady1]

Thanks Jim. ISDN and troubleshooting them is definitely not my forte. I inherited the support of them and what I am familiar with, I've learned on my own. Since this is obviously outside of my expertise, we will call in support. Thanks again