This paper discusses the following topics:
82.1 RS-232
- “82.1 RS-232” on page 1
- “82.2 RS-422/485” on page 1
- “82.3 Universal asynchronous receiver-transmitter protocol (UART)” on page 1
- “82.4 Serial messages” on page 1
- “82.5 Module overview” on page 1
- “82.6 Parser operation” on page 2
- “82.7 Module Settings tab” on page 3
- “82.8 Serial Builder” on page 5
- “82.9 Packetizer operation” on page 10
- “82.10 Enabling packetizer” on page 13
- “82.11 Appendix” on page 13
RS-232 is a single-ended physical layer where the data line is referenced to the signal ground. To overcome noise and signal degradation the line swings between +/- 12V with respect to GND. With RS-232 as with most serial protocols, an idle line is always high, which in RS-232 is classed as -12V (logical one) while a low (logical zero) is classed at +12V, that is, the logical and voltage sense are inverted. The receiver accepts lower than +/-12V. RS-232 is often used for lower data rates, also known as baud rates, typically from 9600 bits per second to 115200 bps.