17.
Which method of signaling gives an automatic warning in case of trunk
failure?
a.
Ringdown.
b.
Plug supervision.
c.
In-band signaling.
d.
In-band supervision.
18.
E&M leads are provided for control of signaling with SF units on 4W
lines.
What is the circuit arrangement of the M lead off-hook
condition?
a.
The M lead causes the tone to cease and ground to be applied
through the E lead.
b.
The M lead causes the tone to cease and battery to be supplied
through the E lead.
c.
The M lead causes the tone to start and ground to be applied
through the E lead.
d.
The M lead causes the tone to start and battery to be supplied
through the E lead.
CHECK YOUR ANSWERS
WITH
LESSON
SOLUTION
SHEET
AND
MAKE
NECESSARY
CORRECTIONS.
33
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