The Electronics Industry Association (EIA) has developed standards for data communication. EIA standards where originally marked with the prefix "RS". "RS" means that it is a recommended standard, but the standards are now generally indicated as "EIA" standards. RS422 was developed for greater distances and higher baud rates than RS232. It also enables a bus like structure with up to ten receivers, but it is not a true multi point network there every node could work as transmitter or receiver.

RS422 is a differential voltage loop interface (balanced differential signal); differential data transmission reduces the effects of ground shifts and induced noise signals.

logical "1" (Mark) is represented by a negative voltage of -3.6V to -6V,
logical "0" (Space) is represented by a positive voltage of +3.6V to +6V,
RS422 can be connected to up to ten receivers,
the data rate is up to 10 Mbps,
cable length could be up to 1.3 km (4000 feet),
the connector is a 37 pin D-Sub connector.

Cat5 cable (shielded twisted pair (STP) or unshielded twisted pair (UTP)) generally exceeds the recommendations for RS-422 and RS-485 systems.

RS422 Connection (37pin D-Sub)
1 GND Shield Ground
2 SRI Signal Rate Indicator
3 n/c
4 SD Send Data
5 ST Send Timing
6 RD Receive Data
7 RTS Request To Send
8 RR Receiver Ready
9 CTS Clear To Send
10 LL Local Loopback
11 DM Data Mode
12 TR Terminal Ready
13 RR Receiver Ready
14 RL Remote Loopback
15 IC Incoming Call
16 SF/SR Select Frequency/Select Rate
17 TT Terminal Timing
18 TM Test Mode
19 GND Ground
20 Receive Twisted-Pair Common
21 Spare Twisted-Pair Return
22 Transmit Data TPR
23 Transmit Timing TPR
24 Receive Data TPR
25 Request To Send TPR
26 Receive Timing TPR
27 Clear To Send TPR
28 IS Terminal In Service
29 Data Mode TPR
30 Terminal Ready TPR
31 Receiver TPR
32 SS Select Standby
33 SQ Signal Quality
34 NS New Signal
35 Terminal Timing TPR
36 SB Standby Indicator
37 SC Send Twisted Pair Common

See also the TIA, standards