Section Il. CONTROLS AND INSTRUMENTS
required by changes in the talk-back circuit, the
21. General
drum speed circuit, and the starting and phasing
All electrical operating controls of Facsimile
circuits on certain models. Input and output
Set AN/TXC-1(*) are located on the sloping front
connections are located on the right-hand end of
panel of Facsimile Transceiver TT-1(*)/TXC-1
the transceiver.
the drum-engaging lever, and the clamp-bar con-
trol knob are located on the drum and its control
The following chart lists the controls of Fac-
mechanism. Controls are the same for all fac-
simile Transceiver AN/TXC-1(*) and indicates
their functions.
simile transceivers, except for minor differences
a. Panel Controls.
Function
Makes and breaks one side of the 110-volt, 60-cycle ac line circuit which
Power ON-OFF switch (S2) --------------
feeds the primary of transformer T11, located in Rectifier Power Unit
PP-86(*)/TXC-1. In the ON position, plate, filament, and screen
voltages are applied to all tubes in the facsimile set. Power is made
available for starting and operating the synchronous motor, subject to
changes made by the selector switch (S1) and STANDBY-MON-TALK
switch (S5).
STANDBY-MON-TALK switch (S5) (Not
In the STANDBY (upper) position, it connects the loudspeaker in the
included in Facsimile Transceiver TT-
circuit and permits the operator to monitor the communication channel.
If both the STANDBY-MON-TALK switch (S5) and the selector
1/TXC-1).
switch (S1) are in the STANDBY positions, the synchronous motor will
not operate. This position is used to receive voice communications
when it is not necessary to have the motor running.
Warning: When using Facsimile Transceivers TT-1B/TXC-1
through TT-1F/TXC-1, the motor may run at a nonsynchronous speed
in any switch position. When the motor is running at synchronous
speed, the drum will revolve or 1 revolution each second, and the
respective 900- or 1,800-cycle audible tones will be heard coming from
the motor laminations.
In the MON (middle) position, it connects the loudspeaker and permits
the operator to monitor the communication channel. The motor is
supplied power and may be started and run at synchronous speed.
This is the normal position for receiving voice communications when
phasing the transmitting and receiving equipments preparatory to
sending and receiving facsimile copy.
In the TALK (lower) position, the loudspeaker becomes the microphone
of a voice intercommunication system. The switch must be held in the
TALK position; if pressure is released, it will snap back to the MON
position. The TALK position is used when talking to the facsimile
operator on the other end of the circuit.
Note. The talk-back circuit operates only when the selector switch (S1) is at STANDBY.
Caution: The talk-back circuit will not function over a radio circuit
that uses Converter CV-2C/TX, TM 11-2252A, unless the converter
is bypassed for voice communication.
Selector switch (S1)---------------------
This control determines the function of the transceiver. Positions and
functions are as follows:
Position
Function
The facsimile transmitting circuit is estab-
TRANSMIT-----
lished. Impulses representing elements of
the facsimile copy are sent out over the
facsimile circuit to the receiver. This is the
normal operating position when the trans-
ceiver is actually transmitting copy. In
this position, the switch also closes the radio
transmitter relay circuit associated with
CARBON MIKE jack J4.
