Diagnostic aids, Other ideas, Look into the lights – Telos ZephyrExpress User Manual

Page 147

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’

and

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

for a few seconds, and then display the date and time

. If things don’t happen

Or at least some date and time. We don’t consider a misset clock to be a major problem.