The maximum cable length for RS-232 is 50ft, but in practice, it depends on baud rate, cable specific capacitance, and ambient noise. The table below contains some rules-of-thumb from experiments done by Texas Instruments years ago.
Baud rate
Maximum range / cable length
19200
50 ft
9600
500 ft
4800
1000 ft
RS232 DB9 Pinout Diagram
RS-232 Maximum Cable Length
The maximum cable length for RS-232 is 50ft, but in practice, it depends on baud rate, cable specific capacitance, and ambient noise. The table below contains some rules-of-thumb from experiments done by Texas Instruments years ago.