Oki OKIFAX 5950 Series Maintenance Manual page 353

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.
OF5750/5950 Series January 2001
A
Do they receive normally?
Yes
7 - 12
No
Check the line and the network.