Modem
A modem (short for modulator/demodulator) can turn a data signal into sound and vice versa, using frequency-shift keying.
Technically, home computers used a modem to save data to cassette tape. In regular use, however, the word referred to a dialup modem in particular — a small box that connected a beige box to a landline, so it could dial up a BBS or the Internet.
Modems tended to be very slow. The C64 could save data to tape, and load it back again, at about 300 bps. 14.4 kbps dialup modems were common in the mid 1990s. ISDN achieved a whopping 64 kbps.
Modulation: FM synthesis | Frequency-shift keying | Frequency shifter | Modem
