What s a good free serial port monitor for reverse-engineering

Question

I m reverse-engineering a serial protocol and getting frustrated by bad tools   Does anyone know of a good  free tool for logging data to from serial ports on Windows   Requirements    Must be free Must not take control of the port  i e  must hook the file APIs or the kernel rather than trying to open the device  Must have some sort of filtering features Writes either human-readable or binary logs  preferably in an easy to parse format   Any ideas   Portmon works  but its logs are difficult to work with and its filters are effectively useless  I ve also tried a few commercial tools and nothing seems to fit the bill

User · Accepted Answer

Portmon from sysinternals  now MSFT  is probably the best monitor    I haven t found a good free tool that will emulate a port and record replay comms  The commercial ones were expensive and either so limited or so complex if you want to respond to commands that I ended up using expect and python on a second machine

User · Answer

I hear a lot of good things about com0com  which is a software port emulator   You can  connect  a physical serial port through it  so that your software uses the  monitored  virtual port  and forwards all traffic to from a physical port   I haven t used it myself  but I ve seen it recommended here on SO a lot

User · Answer

I d get a logic analyzer and wire it up to the serial port   I think there are probably only two lines you need  Tx Rx   so there should be plenty of cheap logic analyzers available   You don t have a clock line handy though  so that could get tricky

User · Answer

I hear a lot of good things about com0com  which is a software port emulator   You can  connect  a physical serial port through it  so that your software uses the  monitored  virtual port  and forwards all traffic to from a physical port   I haven t used it myself  but I ve seen it recommended here on SO a lot

User · Answer

Oops  can t comment yet     but re  Nick and logic analyser  beware  RS232 signal levels not typically Logic Analyser compatible unless you get make a special serial probe  A  proper  RS232 Serial port can use   -12v swings  on all signals  and sometimes more  A laptop sometimes uses 0-5v swings  and often won t work with real serial interfaces  so could work with a vbasic  ttl-level  LA interface

User · Answer

I ve been down this road and eventually opted for a hardware data scope that does non-instrusive in-line monitoring   The software solutions that I tried didn t work for me   If you had a spare PC you could probably build one  albeit rather bulky   This software data scope may work  as might this  but I haven t tried either

User · Answer

I ve been down this road and eventually opted for a hardware data scope that does non-instrusive in-line monitoring   The software solutions that I tried didn t work for me   If you had a spare PC you could probably build one  albeit rather bulky   This software data scope may work  as might this  but I haven t tried either

User · Answer

I ve been down this road and eventually opted for a hardware data scope that does non-instrusive in-line monitoring   The software solutions that I tried didn t work for me   If you had a spare PC you could probably build one  albeit rather bulky   This software data scope may work  as might this  but I haven t tried either

User · Answer

I hear a lot of good things about com0com  which is a software port emulator   You can  connect  a physical serial port through it  so that your software uses the  monitored  virtual port  and forwards all traffic to from a physical port   I haven t used it myself  but I ve seen it recommended here on SO a lot

User · Answer

Oops  can t comment yet     but re  Nick and logic analyser  beware  RS232 signal levels not typically Logic Analyser compatible unless you get make a special serial probe  A  proper  RS232 Serial port can use   -12v swings  on all signals  and sometimes more  A laptop sometimes uses 0-5v swings  and often won t work with real serial interfaces  so could work with a vbasic  ttl-level  LA interface

User · Answer

I hear a lot of good things about com0com  which is a software port emulator   You can  connect  a physical serial port through it  so that your software uses the  monitored  virtual port  and forwards all traffic to from a physical port   I haven t used it myself  but I ve seen it recommended here on SO a lot

User · Answer

I d get a logic analyzer and wire it up to the serial port   I think there are probably only two lines you need  Tx Rx   so there should be plenty of cheap logic analyzers available   You don t have a clock line handy though  so that could get tricky

User · Answer

I ve been down this road and eventually opted for a hardware data scope that does non-instrusive in-line monitoring   The software solutions that I tried didn t work for me   If you had a spare PC you could probably build one  albeit rather bulky   This software data scope may work  as might this  but I haven t tried either

User · Answer

I d get a logic analyzer and wire it up to the serial port   I think there are probably only two lines you need  Tx Rx   so there should be plenty of cheap logic analyzers available   You don t have a clock line handy though  so that could get tricky

User · Answer

I d get a logic analyzer and wire it up to the serial port   I think there are probably only two lines you need  Tx Rx   so there should be plenty of cheap logic analyzers available   You don t have a clock line handy though  so that could get tricky

[serial-port] What's a good, free serial port monitor for reverse-engineering?

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