The Bell 212A modulation scheme defined a standard method of transmitting full-duplex asynchronous serial data at 1.2 kbit/s over analogue transmission lines. The equivalent, but incompatible ITU-T standard is V.22.
Device
The Bell 212 Dataset is a modem used for communicating over telephone lines at 300 or 1200 bits per second.
References
Bell 212A Wikipedia(Text) CC BY-SA