rs-432
rs232 has some limitations: speed 15 m. extension cable, ... EIA produced RS449 to avoid this limitations. RS449 is composed of two stardards: rs423a for asimetric transmission or not balanced and RS422a which used in balanced transmission.
Some caracteristics of rs423:
- 60 metres maximun between two terminas.
- 2Mbps in rs422 or 40Kbps in rs432.
- 37 pins connector and 9 pins connector if a second channel is used
Hope this help.
(Sorry for my english).