EIA-422
<communications, standard> (Formerly "RS-422") An
EIA serial line standard which specifies 4-wire,
full-duplex,
differential line, multi-drop communications.
The mechanical connections for this interface are specified by
EIA-449.
The maximum cable length is 1200m.
Maximum data rates are 10Mbps at 1.2m or 100Kbps at 1200m.
EIA-422 cannot implement a truly multi-point communications network (such as with
EIA-485), although only one driver can be connected to up to ten receivers.
The best use of EIA-422 is probably in
EIA-232 extension cords.
Comparing EIA-422, 423, 449 to RS-232-C (http://www.rad.com/networks/1995/rs232/rs449.htm).
Details on RS-232, 422, 423 and 485 (http://www.rs485.com/rs485spec.html).
