18.
The phantom group shown in figure 70 provides an additional telephone or telegraph circuit from two 2-wire
circuits without using ground return. The number of repeating coils necessary for efficient operation with this
arrangement is:
a.
two.
c.
four.
b.
three.
d.
six.
19.
Assume that a type of circuit was installed in the central office telephone system to permit three telephones and
four telegraph channels to be operated simultaneously. This type of circuit is known as a:
a.
phantom group circuit.
b.
composite circuit.
c.
simplexed-phantom circuit.
d.
metallic and ground-return circuit.
CHECK YOUR ANSWERS AGAINST LESSON 3 SOLUTION SHEET (PACE 193) AND MAKE NECESSARY
CORRECTIONS.
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