Comtech EF Data CDM-760 - Test:) Bert; TEST:) Comp

Front Panel Operation Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
6–66
6.2.4.2 (TEST:) BERT
BER:No Sync Count:0.0E+00 Errs:0.0E+00
BERT:On Patt:2^23-1 Restart ErrIns ()
On the top line – Read-only BER (Bit Error Rate) information is provided as follows:
Parameter
Description
BER
This is the current Bit Error Rate of the demod. This BER figure is only available when BERT is ON.
When BERT is OFF, or if there is a mismatch in pattern selection, or if there is a substantial issue
with the link, this parameter displays “No Sync”.
Count
This is the total number of BERT Pattern bits received by the demodulator since BERT was enabled
or since the last Restart.
Errs
This is the total number of BERT Pattern bits received in error by the demodulator since BERT was
enabled or since the last Restart.
On the bottom line – Use the   arrow keys to select a function. Then:
Function
Instructions / Description
BERT
Press ENTER. Then, use the

arrow keys to select ON or OFF. ON enables the BERT pattern
on the modem Tx and begins the search for the BERT pattern on the demodulator Rx.
Patt
Press ENTER. Then, use the

arrow keys to select a BERT pattern that the modem can be set
to transmit and to search for on receive. Selections are 2047, 2^15-1, 2^23-1. The longest pattern,
2^23-1, is typically used in testing to ensure a solid data sync.
Restart
Press ENTER to reset all counters to 0.0E00.
ErrIns
Press ENTER to insert a single bit error that will be reported by the demodulator locked to the
BERT pattern.
6.2.4.3 (TEST:) Comp
K4 GZip Lossless Compression and Decompression in an optional feature that requires
installation of the Compression Card in the modem.
Bypass: Enable
()
Use the arrow keys to select Enable or Disable. Press ENTER. Note the following:
• With Enable selected, K4 GZip compression is turned off (bypassed) while running a test (the
TEST MODE front panel LED Indicator is lit).
• With Disable selected, this assumes normal modem operation with K4 GZip compression
operable (the TEST MODE front panel LED Indicator is not lit).