EIA-485 definition communications, standard
(Formerly "RS-485") An EIA serial line standard
which specifies 2-wire, half-duplex
, differential line
communications. Maximum cable length is 1200m. Maximum data rates are 10Mbps at 1.2m or 100Kbps at 1200m. EIA-485 can implement a truly multi-point communications network, and specifies up to 32 drivers and 32 receivers on a single (2-wire) bus.
Differential SCSI uses EIA-485.
Details on RS-232, 422, 423, and 485 (http://rs485.com/rs485spec.html).