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EL 4937A
TROLS
5. CONTROLS, CONNECTORS, and INDICATORS (con't)
Qf^/Qprp hook key"-Wlien the instrument is selected to be the ORIGINATE end, the ON/OFF
HOOK key simulates the on~hook or off-hook condition of the originate end. When the instru¬
ment is the TERMINATE end the ON/OFF HOOK key simulates the on-hook or off~hook condition
of the terminate end,
STATUS LEDs—There are four status LEDs that indicate the status of both the originate and
terminating ends of the line, The status lights are:
ON HK ORiG (on-hook originate)
OFF HK ORIG (off-hook originate)
ON HK TERM (on-hook terminate)
OFF HK TERM (off-hook terminate)
D HOLD OTHER--Puts an auxiliary hold circuit on the B jack if the A signaling key is pressed. The
auxiliary hold circuit will be placed on the A jack if the 3 signaling key is pressed, (used to seize
a second 2-wjre circuit for testing)
1, ORIG/TERM key — Selects whether the type of signaling Is originate or terminate,
2 SIG SELECT key--Selects one of the following signaling modes. Lighted LED indicates selected
signaling,
E/M (E and M)
GND START
(ground start)
LOOP (loop start)
LOOP REV BATTERY
(loop reverse battery)
3 FILTER SELECT key~-Selects desired weighting filter for noise measurements and the type of
spectrum for return loss measurement.
4, MEAS SELECT key--Selects one of the following measurements. Lighted LED indicates selec¬
ted measurement.
LEVEL FREQUENCY
NOISE
NOISE W/TONE (noise with tone)
SIGNAL/NOISE (signal to noise)
NOISE TO GROUND
RET LOSS 2W
(return loss 2 wire)
RET LOSS 4W
(return loss 4 wire)
6
MOD
DON
3-1.
6
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i !
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5
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