EIA-422
EIA-422 (formerly known as RS-422 ) is a series of data transmission protocols that specify 4-wire, full-duplex, differential transmission, and multipoint communication . It adopts balanced transmission and adopts unidirectional/non-reversible transmission line with or without enabling end. Different from RS-485, EIA-422 does not allow multiple senders but only multiple receivers. In terms of hardware composition, EIA-422 (RS-422) is equivalent to two sets of EIA-485 (RS-485), that is, two half-duplex EIA-485 (RS-485) constitute a full-duplex EIA-422 ( RS-422).
| internet kit |
|---|
| application layer |
| transport layer |
| network layer |
| link layer |
Some of the key advantages of this standard include RS-423's defined multiple receivers, transmission rates up to 10Mb/s over cable lengths of 12 meters (40 feet), and long-distance data transmission in industrial environments.
The mechanical characteristics of the interface are specified by EIA-530 or EIA-449, however the device only exists when the sender and receiver are paired. The maximum transmission rate of the cable is 10 Mbit/s (for a length of 1.2 meters) or 100 kbit/s (for a length of 1200 meters). EIA-422 cannot realize true multipoint communication like EIA-485, although only one sending end can connect 10 receiving ends.
EIA-422的通常用途是作为RS-232的扩展。有一種和RS-232兼容、使用mini-DIN-8端子的变种EIA-422曾廣泛的使用在蘋果電腦的硬體上，不過後來已經被USB所取代。目前EIA-422 (RS-422）與 EIA-485 (RS-485)的應用主要集中在工業控制環境，特別是長距離數據傳輸，如連接遠端周邊控制器或感測器。