Commodore 1670 Modem
From Computer History Wiki
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The 1670 was a 1200 baud, Hayes compatible Modem. This modem plugged into the special parallel 'modem' slot on the back of the Commodore 64 & the Commodore 128. Unlike the prior modems, this modem supported the popular Hayes command set (aka AT commands), and could be used with a wide variety of terminal programs.
