Telenetics MIU202T - Manual (Page 21)

MIU202T Installation, Operation & Diagnostics Edition: April 4, 1998 Page 19
(c) REMOTE DIGITAL LOOPBACK – 4/Wire Network (Figure 5)
Configure both the local and remote modems as follows:
Switch 1 = ON (TxA = 0dBm)
Switch 3 = ON (RxA = -33dBm)
Switch 4 = OFF (RTS/CTS = 35ms)
Switch 5 = ON (RTS/CTS = 35ms)
Switch 6 = ON (Constant Carrier mode).
Switch 7 = OFF (4-Wire)
Switch 8 = ON (Line Termination = 600 ohms)
Switch 9 = ON (Soft Carrier Turn Off = ON)
Connect TxD to RxD at the remote modem.
Transmit a test message from the local modem and confirm that the same
message is received back at RxD on the local modem with no data errors.