The Free On-line Dictionary of Computing (30 December 2018):

EIA-422
RS-422

    (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://rad.com/networks/1995/rs232/rs449.htm).  Details
   on RS-232, 422, 423 and 485
   (http://rs485.com/rs485spec.html).

   (2002-10-05)