Lesson 3/Learning Event 3
All signals entering and leaving the AN/MSQ-73 are
either VF (none higher than 4 kHz) or DC telegraph. Circuits with signals
that exceed these limits must be connected at another point in the system.
For example, the line side of telephone carrier terminals cannot be
connected through the AN/MSQ-73; the composite signal line shunts the
shelter to connect to a wideband radio terminal or suitable cable at the
point of connection with the facility. The AN/MSQ-73 has not facility for
connecting either spiral-four or coaxial cable.
All connections of
multichannel telephone terminals takes place on the loop side of the
channels where VF signals appear. Multichannel telegraph terminals can be
connected either on loop or line sides, because the loops may be either DC
or VF and the line composite signal is in the VF range.
c. Circuit Capacity.
The circuit capacity is provided by 872 wire
pairs, divided as follows.
(1) VF 4W--480 pairs gives 240 circuits (one pair for each direction of
(2) VF 2W-96 pairs (one pair for each circuit).
(3) DC teletypewriter 4W--240 pairs gives 120 lines (one pair for each
direction of transmission.
(4) Spare--56 pairs.
d. Jacks and Patching Cords.
Only single jacks are used (no twin
jacks), with tip, ring, and sleeve connections. Tip and ring always carry
the circuits. Patching cords for the most part use single plugs with tip,
ring, and sleeve connections.
Cords with twin plugs are used for
convenience in patching 4W VF circuits; circuit jacks are spaced side by
side in the patch panels to make this possible. Most jacks are wired for
Learning Event 3: PLAN LAYOUT, RIGHT SIDE
The plan layout of the AN/MSQ-73 is shown in figure 3-4. The right
side, left side, front, and rear are indicated on the diagram.
designations will be used when referring to pictures of the interior of
a. Cable Patch Bays.
Cable patch bays 1, 2, and 3 (figure 3-5)
provide direct access to all VF lines terminated at the an. Each of these
three bays contains VF jackfields, adjustable attenuators, and a 48-volt
In addition, bay 1 includes a writing shelf and two
distribution assemblies for the 48-volt DC power.
Bay 3 also has a