12. When the hand generator is used to signal on an LB line, any signal current through the telephone will
weaken the outgoing signal. The set of open hookswitch contacts that excludes all signal current from the local
set is
a. 1 and 2.
c. 5 and 6.
b. 3 and 4.
d. 7 and 8.
13. Assume the handset-headset is connected to Telephone Set TA-312/PT in a common-battery system. In
normal operation, the contacts that close the signal circuit to the operator are
a. 1 and 2 of switch S2.
b. 3 and 4 of switch S2.
c. 3 and 4 of switch S3.
d. 8 and 9 of switch S1.
14. The internal resistance of the self-contained transmission battery is relatively low. Voice-frequency
currents are prevented from taking this low-resistance path by
a. coil H.
c. resistance B.
b. inductor E.
d. holding coil J.
15. When Telephone Set .TA-312/PT is used on common-battery loops, the length of the line loop will affect
the voltage that is supplied to the telephone set. The variations in the line voltage are somewhat stabilized by the
action of
a. inductor A.
c. capacitor K.
b. resistor C.
d. varistor CR1.
16. The antisidetone circuit of Telephone Set TA-312/PT is designed so that voice currents in the receiver
will be minimum while transmitting and maximum while receiving. This is possible because
a. varistors CR1 and CR2 reduce voice currents during transmission.
b. the press-to-talk switch reduces voice currents through the receiver when transmitting.
c. voice currents in coils A and H are opposing while transmitting, and aiding while receiving.
d. voice currents entering the telephone are stronger than the voice currents leaving the telephone.
410 L3
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