Figure 2-3. 2- Wire VF channels.

TM 11-5895-1123-34

pable of processing 12 VF channels. The 12 channels

Patch panel can be fed through the CU-1819/T isolators

can be any combination of four-wire VF channels using

to be converted back to high level TTY voltages for field

1600-Hz or 2600-Hz signaling frequencies and/or two-

users or be used in conjunction with the one remaining

wire VF channels using 20-Hz signaling frequencies.

FSK converter to supply as many as four low level TTY

b. Figure 2-3 shows a block diagram for one

channels for field users and/or the internal TTY.

channel of four-wire VF and one channel for two-wire VF.

2-4.

Voice Frequency Processing System

a. The Voice Frequency Processing System is ca

Figure 2-3.

2- Wire VF channels.

c. The main difference between the two types of

stage which is responsible for ensuring that the signal on

each Tx line from the user is set for a 0 dBm level.

VF processing is in the line conditioning equipment.

d. For four-wire VF channel processing, the line

This level adjustment is accomplished by either inserting

an amplifier to boost the signal

conditioning equipment consists of a level adjust

2-6