TROUBLESHOOTING 9-5

Other Ideas

Constantly apply sanity checks. Almost thirty years ago, the Firesign Theater put out an
album called “Everything You Know is Wrong”. Use that as your guiding philosophy in
troubleshooting a Zephyr set-up. For example, just because you checked the Telco line
last night and it was fine doesn’t mean it’s OK now.
At 3:00 AM when the problems seem intractable and you’re ready to give up engineering
as a career, remember that the system has worked and will work again. Relax: you’re
smarter than the ISDN is, and you’ll figure it out.
Diagnostic Aids
Fortunately, ZephyrExpress has some features designed to aid your troubleshooting ef-
fort.

Look into the Lights

You can learn a lot about an error condition by observing ZephyrExpress’ panel lights:
Front-panel LEDs
All of ZephyrExpress’ LEDs should light for a few seconds on power-up or reboot. The
MIC1 and MIC2 routing switches’ A and B LEDs will glow red; the other routing LEDs glow
green, the meters are fully on, and the LOCK and SAFE LEDs glow red. It’s a veritable
Christmas Tree. If you don’t see these lights, chances are very good you’ve got a power
supply problem.
The LOCK LEDs light when the decoder is receiving valid data. If they’re off, chances are
the Receive mode doesn’t match the distant unit’s send mode. If it’s flashing, both units
are probably in Layer 3 but in different channel or stereo modes. In either case, the cause
might also be bad data due to equipment or ISDN problems.
The SAFE LED should either be steadily on or off, depending on how the SAFE MODE
switch on the rear panel is set. If SAFE is blinking, it either means:
• Someone left ZephyrExpress in one of its loopback modes when they last turned the
system off. Use the Codec menu to turn Loopback: Off.
• You have a European ISDN card (no NT1), and the ISDN circuit is disconnected or
dead.
• There is a hardware problem preventing ZephyrExpress’ codec from synchronizing
with the telco’s clock.
Normal operation is impossible until SAFE stops blinking.
LCD
The LCD display should show the word Initializing... for a few seconds, and then the
Status Screen should appear. The upper right corner of the Status Screen should say
Loading... for a few seconds, and then display the date and time1. If things don’t happen
1 Or at least some date and time. We don’t consider a misset clock to be a major problem.