3-26
Q25. What does the color red indicate on a tty patch panel?
CRYPTOGRAPHIC EQUIPMENT.—Cryptographic equipment is used to ENCRYPT and
DECRYPT tty messages that require security handling. (Encrypting is the method used to code a
transmitted message; decrypting is used to decode a received message.) To code or decode any message,
the send and receive cryptographic equipment must be compatible.
REMOTE TRANSMITTER CONTROL UNIT.—The remote transmitter-control unit is mounted
close to the kybd and permits remote control of the transmitter (xmtr). It has a transmitter power on-off
switch, a power-on indicator lamp, a carrier-on indicator lamp, and a three-position rotary selector switch.
For rfcs operation you set the switch to CFS SEND to transmit and to CFS REC to receive. Use the
TONE S/R position for both transmitting and receiving afts signals.
An audio frequency tone-shift system will be discussed later in this chapter.
TRANSMITTER TRANSFER SWITCHBOARD.—The transmitter transfer switchboard is used
in this system to connect the remote transmitter control unit to the radio transmitter.
RADIO TRANSMITTER.—The radio transmitter transmits the tty signal. You should be careful
when tuning the transmitter for rfcs operation. The carrier frequency setting is critical and must be
properly set to ensure a correct output from the transmitter.
Q26. What are the functions of cryptographic equipment?
Rfcs Receive System
Figure 3-24 shows the rfcs receive system used to receive the transmitted signal and translate it back
to a usable output. You should look at this figure while studying the units in this section.
