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LIMITED-DISTANCE MODEM 56/64
4.4 Test Mode
The Limited-Distance Modem performs two V.54 test
loops: analog loop (ANA) (V.54, loop 3) and remote
digital loop (REM) (V.54, loop 2) (see
Figures 4-1
and
4-2
). Both loops can be controlled either by a manual
switch, or by the DTE interface Pin 18 (ANA), and Pin
21 (REM). When using the Modem (V.35 version) with
the mating cable (DB25 to 34-pin), the loop-activating
pins are JJ for ANA and HH for REM. The TEST LED
lights, and Pin 25 (Circuit 142) turns ON when the
modem is in one of the diagnostic loops. (When using
the V.35 model with the mating cable, Circuit 142 uses
Pin KK.) Activation of both loops from the DTE
interface is controlled by S9 and S10 (see
Table 3-1
).
NOTES
To return to normal operation, move the switch to the center
position, or if using the DTE interface (Pins 18 and 21),
switch to OFF. The TEST LED and Pin 25 will turn off
automatically.
