FIGURE 1-3. MODEM: TYPICAL CONFIGURATION FOR PONY OPERATION
1 Teletypewriter (local or remote send) dc mark and space pulses are sensed by the modem.
2 The modem converts tty dc pulses to tty tones for transmission.
3 With LOCAL-REMOTE switch on control panel (AN/GRC-142,-122) or switch assembly (AN/
GRC-142A, -142B, -122A, -122B) in REMOTE or LOCAL position, tty dc pulses are sent to [tty
(REMOTE)] on local receive circuits and applied to page printers or tape punches for message
4 Received tty tones are converted by the modem into dc mark and space pulses.
When connected in the pony circuit configuration, the modem provides
local teletypewriter communications between the local receiving teletype-
writer base and a remote (pony) teletypewriter located somewhere in the
nearby area of the base.