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Serial port capture to PCAP

This tool can capture serial port traffic and store all data in PCAP format. It is later possible to open it by Wireshark and analyze it. It is also possible to use realtime mode with named pipe instead of file.

This tool was created to capture Modbus-RTU on RS-485 but can be used to any other similar traffic.

Tutorial on using this capture is on YouTube

Tool is only for command line,

usage: mono SerialPcap.exe [options] <portName>

Option Description
-b, --baud=VALUE Serial port speed (default 9600)
-y, --parity=VALUE o (=odd), e (=even), n (=none) (defaul none)
-p, --stopbits=VALUE 1, 2 (defaul 1)
-g, --gap=VALUE Inter frame gap in miliseconds (default 10)
-d, --dlt=VALUE Data link type in pcap format (default 147)
-o, --output=VALUE Output file prefix (defalut port name)
--pipe Use named pipe instead of file
-h, --help Show this message and exit

portName is COM1, \\.\COM15 or /dev/ttyUSB0 or similar definition.

It is possible to run this tool using Mono on Linux or using .Net framework on Windows.

Pipe (realtime) mode on linux

It is possible to run the application in pipe mode, so you can see realtime traffic in Wireshark. On linux, you should perform these commands

mkfifo /tmp/wspipe
wireshark -k -i /tmp/wspipe &
mono SerialPcap -o /tmp/wspipe --pipe [options] <portName>

More info on Wireshark capture pipes can be seen on


Serial port PCAP capture tool not just for Modbus-RTU




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