9-12 TROUBLESHOOTING
Condition: No Audio In Both Directions
Does ZephyrExpress’ loopback isolate the problem?
See above for tips on using the loopback modes.
Is the ZephyrExpress mode set properly?
Your Codec: transmit mode must match their receive mode. Their transmit mode must
match your Codec: receive mode.
Sometimes cycling between modes can clear a decode problem.
Is audio properly connected and configured?
Do the loopback tests described earlier. Make sure the audio menu settings are correct.
Try different microphones and cables.
hHOT TIP!

Use ZephyrExpress’ POTS facility to place an analog call over the ISDN line to a

standard phone at the distant studio, so you can compare notes on the codecs’

settings.

Condition: Audio In One Direction Only
You’ve already checked that the codec modes at both ends are set properly, right?
This problem can be either analog or digital in nature. Unlike analog telephone lines, the
two directions of a digital line are mostly independent. It is possible to have a telephone
channel failure in one direction only. Try these steps to force the network to use a differ-
ent path.
1. What happens if you try a different long distance carrier for the call?
2. Try the call at 56kbps vs 64kbps (or vice versa)?
3. Try reversing the direction of the call?
4. Try placing a local call as a long distance call?
Are audio signals and connections OK?
Try changing the routing switch settings, using a different ZephyrExpress input or out-
put, using the other channel, or placing an L3-dual call on the other line.
Condition: Audio Distorted
Are the Audio: Microphone Sensitivity settings correct? Is the microphone wired
properly for a balanced input?
If the MIC1 or MIC2 routing LEDs light up red, the sensitivity is too high and you’re sure to
get distortion.