Sniff Serial Connection

Windows

• My favorite: Advanced Serial Port Monitor v4.1.5 2011-03-28.
  Works with Windows 7, somewhat limited in the free edition but good for me.
  http://www.aggsoft.com/serial-port-monitor/serial-port-sniffer.htm
• 232Analyzer has a free edition: http://www.232analyzer.com/232default.htm.
• Portmon
  http://technet.microsoft.com/en-us/sysinternals/bb896644.aspx
• Advanced Serial Port Monitor v3.00
  http://www.kmint21.com/serial-port-monitor/
  I don’t know if this works with newer Windows versions.
• SAL232 – RS-232 Serial Loger & Analyzer
  http://www.hw-group.com/support/SAL232/index_en.html

Also see RS232 Packet Sniffer Question on superuser.com.

Linux

• jpnevulator
  http://jpnevulator.snarl.nl/
  http://manpages.ubuntu.com/jpnevulator
  monitor and sniff two serial ports using jpnevulator --ascii --timing-print --tty /dev/ttyS0:SB9600d --tty "/dev/ttyUSB0:Motorola MTM800" --read
• Serial line sniffer – slsnif
  http://sourceforge.net/projects/slsnif/
• You may be able to use pyserial.
• strace – You can trace system calls and signals including serial communication. See strace man page for the details.
• Moni
• moserial
• http://freecode.com/projects/linuxserialsniffer

Mac OS X

• Serial Tools: http://www.w7ay.net/site/Applications/Serial%20Tools/