Telos ZephyrExpress Some Error Conditions, No functionality the box is totally or partly dead

•If either unit can lock to itself, consistently, while looping through the other unit’s Far Loopback, then the ISDN connection is good.

•If neither unit can lock to itself then the ISDN connection is failing somewhere. This can be because some part of the connection doesn’t support the bitrate you’ve chosen. It can also happen in the unlikely event that both codecs are broken.

Using two Far Loopback tests, to check units at both ends, will often tell you exactly where a problem lies. For example: If they can’t hear you during normal operation, but you can hear yourself when they’re in Far Loopback, you know both your transmit coder and receive decoder are working and the line is good. Have them test their codec with your ZephyrExpress in Far Loopback. If they can’t hear themselves either, you know it’s their receive decoder. If they can hear themselves, the problem is an incompatibility between codecs: try a different mode.

Some Error Conditions

No functionality; the box is totally or partly dead.

Does ZephyrExpress have power?

Does the outlet have power? Is the power module’s fuse blown? The green LED on the power module should be lit. If it is, then the LCD display on ZephyrExpress should be

wlit1. You can test the power supply for the voltages as listed in section 3, Hardware. Since switching supplies must be tested under load, you’ll have to dismantle the its XLR con- nector, and leave the insert plugged into ZephyrExpress, while checking.IMPORTANT NOTE!Do not connect or disconnect the 4-pin XLR power connector on the rear of

ZephyrExpress while the power is on. If youÕre probing voltages with the con- nector disassembled, make sure the XLR insert stays in place the whole time that power is applied.

Disconnecting the power supply while itÕs powered can damage ZephyrExpress or erase its memory.

Does ZephyrExpress have basic functionality?

Upon initial power-up, 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 time.

1If the LCD doesn’t light, check that the backlight and contrast are correctly set. See page 9-6.

9-10 TROUBLESHOOTING