Transmission Problem - Oki OKIFAX4550 Maintenance Manual

7.7

Transmission Problem

This section explains how to localize the cause of problems occurred after completion of connection
with a remote station.
Step 1:
Set MH ONLY (Technical function
No. 12) to ON.
Step 2:
Set HIGH-SPEED MODEM RATE
(Technical function No. 13) to 4800 bps.
Step 3:
Adjust send signal power level.
(Technical function No. 21)
Step 4:
Set ECHO PROTECTION (Technical
function No. 11) to ON.
Test other fax machine under the same
conditions, especially concerning
Step 1-4.
The hardware of the troubled fax
machine may be damaged.
Go to 7.13 (High-speed Modem Test)
to localize the cause.
Description: Protective tone is 1700 Hz/200 ms.
This signal is added to training signal to protect the training signal against echo
as follows.
41309401TH Rev.4
Start
Solved?
Solved?
No
Solved?
No
Solved?
No
Do they transmit normally?
Yes
TX
TR
Protective tone
1700 Hz/200 ms
Yes
Yes
Yes
Yes
No
Check the line and the network.
Note: Even if the high-speed modem test
results in success, 300 bps signal route
remains unchecked. In that case, the
most suspected unit is MCNT Board.
message signal
Return to section 7.1
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