User manual

Section 7

TESTING and DIAGNOSTICS

7-3

7.4 Remote Digital Loopback (RDLB)

This test will verify the receive and transmit sections of both DPX-213 modems and the

phone line in both switched network and leased line operation.

The Remote Digital Loopback test is initiated by typing the escape sequence followed by

the command

at&t6K

In asynchronous modes, you will now get one of two messages on your screen: "LOOP

GRANTED" if the remote modem is able to support loopback testing or "RDL DENIED"

if the remote modem either cannot support RDLB or has previously issued the AT&T5

command.

The DPX-213 modem which is in RDL mode will display "RDL ACCEPTED" if an RDL

request has been received or one or more "RDL DENIED" messages if an RDL request

was received but AT&T5 was set.

During loops, the OH LED will flash. Once the loop is established, all data sent by the

local DPX-213 will be echoed by remote modem and appear on your terminal.

Exit the test by issuing

+++

escape sequence then entering

at&t0K

Return to the data state with the ATO command.

Figure 7.2 Remote Digital Loopback