Columbia University Computing History   

DEC VT520 Terminal with Acoustically Coupled Modem

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DEC terminal with modem and phone
Rear view
A Digital Equipment Corporation VT520 terminal (1993) with its serial port connected to an Anderson Jacobson Model A 242 modem (1970s, see closeup) with a dial telephone handset plugged into its mating cups. To dial, the modem translates between the PC's ASCII characters (e.g. telephone number) and the tones or clicks recognized by the telephone network for dialing. The inset shows the connections between terminal, modem, and telephone (click image to enlarge).  Photos:  Frank da Cruz, 2011.
Columbia University Computing History Frank da Cruz / This page created: 1 October 2021 Revised: (not yet)