Lesson 3/Learning Event 2
amplifier gains or attenuator losses so that the levels in and out of the
circuit patch bays are equal.
If the levels are unequal, the technical
controller must make the changes in amplifier gain and attenuator loss not
only to meet the requirements of the circuit patch bays in the AN/MSQ-73,
but also to accommodate the equipment levels.
(2) Content compatibility. They type of signal must be known before an
attempt is made to interconnect circuits.
Ordinarily, a signal in the
voice range passing through a tactical communication terminal will
likewise pass through a strategic communication terminal.
A problem
arises when the channel bandwidth capability of the two terminals is
different.
The determining factor in this case is the bandwidth of the
narrowest of the two connected channels.
(3) VF telegraph.
VF line signals between telegraph terminals can
interface at the VF patch boards, provided the terminals themselves
exhibit compatibility.
Signal compatibility of VF telegraph terminals
involves channel frequency assignments, amount of shift between mark and
space, and signal sense frequency (mark high and space low, or space high
and mark low).
(4) DC telegraph.
Isolation relays in the AN/MSQ-73 allow for
flexibility in connecting DC telegraph loops.
Problems involving
different values of loop current as well as interfering battery are
greatly minimized by these relays.
Moreover, these relays permit
connecting the metallic circuit wire pairs used by tactical terminals to
single-wire ground-return circuits used in strategic communication
terminals.
(5) Signaling . They type of signaling plays a most important part in
the compatibility picture.
Some systems use 20-5z ringdown, others use
1,600-Hz in-band signaling, and still others use 2,600-Hz in-band
signaling.
Some systems use E&M leads, and others use pulse-link
The AN/MSQ-73 is designed to interconnect all of these
signaling systems.
Learning Event 2: GENERAL DESCRIPTION
Communications Technical Control Center AN/MSQ-73, shown in figure 3-
1, is an air-transportable communications technical control center used to
patch, monitor, and test voice and teletypewriter circuits.
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