Section III. THE TECHNICAL CONTROL FACILITY

TM 11-5895-1012-10

voice frequency channel that has a range from

(4) Exchanges traffic between users whose equip

300-2800 Hertz (Hz) (2500 Hz bandwidth, (nominal 3

ment operates at different speeds and use different

kHz channel)) or 300-3400 Hz (3106 Hz bandwidth

codes and formats.

(nominal 4 kHz channel)). There are some instances,

c. The AUTODIN interface with a DCS Station is

such as with television or other wideband signals,

illustrated in figure 2-4. AUTODIN tributary stations

where the composite tones require a wider bandwidth.

are connected to the AUTODIN Switching Center

In these cases two or more adjacent channels are

(ASC) directly or via AUTODIN conditioned trunks of

specially prepared for transmission of the wideband

the Automatic Voice Network (AUTOVON). The ASC

signal.

is connected for transmission to another ASC via the

a. The voice frequency speech signals can originate

DCS Station which acts as the gateway to the DCS.

from 2-wire or 4-wire instruments with almost any

The traffic is cleared through the station and routed

type of signaling, The power for this circuit is gen-

out on predetermined and preconditioned circuits over

erated as the user speaks into the telephone and the

cable, radio, or satellite systems. These circuits can be

frequency complexity of the signal is that of ordinary

over Government owned facilities or over leased facil-

ities.

speech.

b. DC teletype signals originate at the teletype

d. The AUTODIN Switching Center can be con-

machine and consists of a series of coded pulses, (each

nected to another ASC over the AUTOVON as a

one unique to a keyboard character) where a direct cur-

primary route or, in the event of a failure of a primary

rent is either flowing or not flowing. The teletype

route, as a backup circuit through the establishment of

signal can be passed through the station as dc to

on-call patches. In addition, users of AUTODIN who

another teletypewriter, but most usually it is inputed

do not require full time access to the ASC can be con-

nected to the switching center over AUTOVON on a

to voice frequency carrier telegraph equipment where

the pulses generate tone signals for one channel of the

call-up basis. In cases where AUTODIN is routed over

VFCT composite output tone.

AUTOVON for restoral or for non-full period users of

the AUTODIN to gain access to the ASC, it is the

c. Voice frequency carrier telegraph systems accept

from 2 to 16 or more teletypewriter signals and multi-

responsibility of the technical controller at the ASC to

plexes the tones generated by each teletype signal into

establish the path. The controller dials up the distant

ASC or user, establishes voice contact, makes the re-

a composite "tone package". Each teletypewriter signal

occupies a different portion of the frequency spectrum

quired equipment connections to the circuit, and then

turns the circuit over for digital communications. Af-

of the tone package, which is then transmitted over a

ter restoral of normal routing or at the end of the user

single voice frequency channel.

real-time schedule, the originating technical controller

d. Data and facsimile terminal equipment functions

coordinates the release of the called-up circuit.

in the same manner as a VFCT terminal. In converts

the intelligence from mechanical linkage or light

2-14. Types of Signals

intensity into a unique data stream or series of tones

A technical controller can expect to find signals from

which can then be transmitted over a single voice fre-

any type of terminal equipment passing through the

quency channel. Data signals can originate at a single

TCF. The signals from these equipments include but

data terminal or from an AUTODIN Switching Center.

are not limited to dc teletype loops, speech, data,

e. At the Technical Control Facility the controller

facsimile and voice frequency carrier telegraph

monitors and tests these signals at the voice frequency

(VFCT). The signals may be broken down to a channel

level, except in those instances where a dc teletype

level or pass through the Technical Control Facility at

loop appears at a dc patch panel. Various types of test

the group or supergroup level. The terminal equip

equipment, which will be discussed later, are available

ment generating the data, facsimile and VFCT signals,

for the technical controller to check the quality and

produce a composite tone in the voice frequency range

level of the signals passing through the station.

and the tones are then normally transmitted over a

Section III. THE TECHNICAL CONTROL FACILITY

2-15. General

As noted in the previous section, the communications

a. The Technical Control Facility (fig. 2-5) is that

paths can be over any of the following transmission

element of a communications network that provides

media singly or in serial combinations:

the technical control, interfaces transmission elements

(1) Submarine cable.

of the DCS, and interfaces the user with the System.

(2) Land-line cable or wire circuits.

The management of the communications paths is done

(3) High frequency radio circuits.

at the TCF and subordinate Batch and Test Facilities.

(4) Tropospheric scatter radio circuits.

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