3.
Interface problems can be reduced by using telegraph relays to
isolate telegraph circuits.
Telegraph relays make possible the
patching of two circuits which have
a.
full-metallic and single-wire ground return conductance paths,
neutral signals on one circuit with polar signals on the other,
and dissimilar speeds of transmission.
b.
neutral signals on circuit with polar signals on the other,
dissimilar speeds of transmission, and dissimilar values of
current.
c.
dissimilar speeds of transmission, dissimilar values of current,
and full-metallic and single-wire ground return conductance
paths.
d.
dissimilar values of current, full-metallic and single-wire
ground return conductance paths, and neutral signals on one
circuit with polar signals on the other.
4.
The correct way to patch circuits through a DC telegraph patch board
is to patch first to a series jack in a
a.
cold circuit and then to a series jack in a hot circuit.
b.
hot circuit and then to a series jack in a cold circuit.
c.
cold circuit and then to a tip-only jack in a hot circuit.
d.
hot circuit and then to a tip-only jack in a cold circuit.
5.
The operating procedure used by a technical controller requires that,
after placing or removing a patch on a DC telegraph patch board, he
must
a.
check telegraph distortion.
b.
send reversals over the line.
c.
turn off the unused teletypewriter.
d.
measure circuit current and readjust it if necessary.
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