PictureTel Concorde 4500 Servicing Manual page 9

Receiving a Nondialed Call from an X.21 DCE .............................................................. 3-20
V.25 bis Call Setup and Disconnect............................................................................................ 3-21
Placing a Dialed Call with a V.25 bis Interface ............................................................... 3-22
Receiving a Dialed Call from a V.25 bis Data Unit......................................................... 3-23
Dialing from a V.25 bis Data Unit Keypad ...................................................................... 3-25
Throughput Limitations............................................................................................................... 3-26
Chapter 4
Troubleshooting
Safety Requirements....................................................................................................................... 4-1
Required Tools and Test Equipment............................................................................................ 4-2
Diagnostic Procedures.................................................................................................................... 4-3
Verifying Power-On ....................................................................................................................... 4-4
Pass-Fail Status ...................................................................................................................... 4-4
Fault Log ................................................................................................................................. 4-5
Board Replacements.............................................................................................................. 4-6
Basic Troubleshooting Procedures ............................................................................................... 4-6
No System Power .................................................................................................................. 4-7
No Display on the Monitor .................................................................................................. 4-9
No Audio .............................................................................................................................. 4-11
Network or Communications Failure .............................................................................. 4-13
Peripheral Failure ................................................................................................................ 4-16
Warning Messages........................................................................................................................ 4-21
Verifying Electrical Voltage......................................................................................................... 4-24
Installation Checklist .................................................................................................................... 4-26
Technical Tips................................................................................................................................ 4-26
Isolating a Problem with Port 1 and Port 2...................................................................... 4-30
Loopback Tests .............................................................................................................................. 4-31
Running the Local Video/Audio Loopback Test ........................................................... 4-34
Running the Local Channel Loopback Test..................................................................... 4-35
Running the Remote Video/Audio Loopback Test ....................................................... 4-36
Running the Remote CSU Loopback Test........................................................................ 4-37
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