User`s guide

Test Mode Operation
Modem 3600 7-3
For example, to run the self test analog loopback test for 30 seconds,
enter
ATS18=30&T8
The modem should respond with 000 after 30 seconds.
Testing the Local Modem
Test local operation with the modem offline in command mode. Use
LAL and LAL/TP to test the local modem and the communications to
the local DTE.
Note
Figures 7-1 through 7-5 include LED test indications. These
indications are valid when DTE options are set by factory
option set #1 and RTS is active from the DTE. Where
indicated, RD and/or TD may be on, off, or flashing
depending on the type of DTE and its operating state.
Local Analog Loopback &T1
In Local Analog Loopback the modem transmitter connects to its
receiver so the analog signal normally sent over the telephone line is
received locally.
If operating on leased lines, the lines are terminated into 600 ohms
(Figure 7-1). If off hook on a dial-up line, the modem is forced on hook.
Figure 7-1. Local Analog Loopback
(4-Wire Operation and 2-Wire Operation)