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| Section 5
Condition: Intermittent ISDN Problems
These are among the most difficult kinds of problems to solve. Rest assured, however, that we have yet to
lose one!
First try disconnecting the ISDN line and waiting a full 60 seconds (leave the iQ6 on) and then reconnect
the line.
Does the problem occur on all of the ISDN BRI circuits or just a single BRI circuit (2 “lines”)?
If the problem is limited to a single BRI circuit (ie both “lines” on that BRI are showing the problem) then
the problem may be with that BRI line or with that ISDN interface card. Move the BRI line in question to a
different interface card (don’t forget to reprogram the SPIDs).
Are the problems confined to incoming calls only?
In this case, check the ISDN (Telco) protocol setting in the TEL. If you believe your line is DMS Custom try
the National ISDN setting, or vice versa.
Are the DNs entered correctly? If so, try using 10 digits rather than 7 digits, or vice versa. What is consis-
tent about the problem (look for patterns)?
Keep watching for a pattern. Enlist the help of the users. We’ve seen apparently random problems that we
eventually discovered only occurred when it rained, or on a certain day each week, or at a certain time of
day, or only when another line was in use. In other cases, it was related to temperature or dirty AC power.
Assume nothing and suspect everything. Leave no stone unturned while searching for the answer.
Any other ISDN troubleshooting tips?
An important tool for troubleshooting incompatibility/programming problems is the iQ6’s integrated
ISDN analyzer. This enables you to look at the transactions between the Telco line and the iQ6, so that a
judgment can be made as to whether the problem lies within the iQ6 or with the programming of the Telco
switch.
The usual cause for an inability to dial is a Telco problem, such as a configuration error.
If you are convinced that the problem lies with the ISDN line configuration, you may be able to convince
the Telco to have an engineer look at the line with an analyzer. This works much like the iQ6 internal
analyzer, but with more detail, and in a format that is more readily understandable by telephone people.
This procedure may sometimes be the only way to get attention to a line problem. It is hard to deny evidence
provided by their own gear.
In rare cases, there could be a software bug in the iQ6 that reacts badly to something coming from the ISDN
line. Telos customer support will communicate the problem to our engineering for resolution.
5.5 Replaceable Modules and Hardware Servicing
WARNING - DANGER
Remove all connections, including the Telephone, Audio, and Electrical Mains Power cord
before opening the unit. Failure to do so could result in injury or death. Do not open the unit
unless you are qualified to do so.
Removal of the top plate gains access for service. To do so, remove the 10 Philips head screws.
