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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.
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
(Table 7-1). If off hook on a dial-up line, the modem is forced on hook.
For 2-wire operation, Analog Bilateral Loopback is invalid. In 4-wire
operation, Analog Bilateral Loopback connects the receive line to the
transmit line through a buffer amplifier.
Figure 7-1 Local Analog Loopback
(4-Wire Operation and 2-Wire Operation)
V.3400
Test Mode Operation
7-3
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