NOMENCLATURE CROSS-REFERENCE

TM 11-5805-387-20-2

1-7. NOMENCLATURE CROSS-REFERENCE

OFFICIAL NOMENCLATURE

COMMON NAME

Modem

Modem Radio Teletypewriter MD-522A/GRC

NOTE

Official nomenclature must be used when filling out report forms onlooking

up technical manuals.

Section II. EQUIPMENT DESCRIPTION AND DATA

1-8. EQUIPMENT CHARACTERISTICS, CAPABILITIES AND FEATURES

Refer to Operator's Manual TM 11-5805-387-10-2.

1-9. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS

Refer to Operator's Manual TM 11-5805-387-10-2.

1-10. EQUIPMENT DATA

Refer to Operator's Manual TM 11-5805-387-10-2.

1-11. SAFETY, CARE AND HANDLING

Observe all WARNINGS, CAUTIONS and NOTES in this manual. This equipment can be extremely

dangerous if these instructions are not followed.

Section III. TECHNICAL PRINCIPLES OF OPERATION

1-12. TECHNICAL PRINCIPLES OF OPERATION

When the modem is used as part of a radio teletypewriter system (fig. 1-1), its modulator section

accepts current pulses in a standard code from a sending teletypewriter and converts them into audio

tones; its demodulator section receives audio tones from an external source and changes them into

current pulses which operate a receiving teletypewriter. As part of a landline teletypewriter system

(fig. 1-2), the modem functions the same as described above. However, incoming and outgoing signals

can be received from, or applied to, telephone isolation amplifiers rather than radio equipment. As part

of a pony circuit setup (fig. 1-3), the modem provides teletypewriter communications between the local

receiving teletypewriter base and a remote (pony) teletypewriter.

NOTE

See TM 11-5805-367-34-2 for more extensive explanations on principle

of operation.

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