This is the homepage of jpnevulator. What once started as a Jackpot Navigator emulator (hence the strange name) is now a nice serial sniffer and you can use it to send data on a serial line too. It's sort of like a very simple terminal emulator, like picocom. But jpnevulator uses hexadecimal byte values to display and send along the line. Very handy indeed if you are working a lot with serial protocols.

jpnevulator is released as Free Software under the GPL license. See the file COPYING in the source tarball for more information.

For your convenience you can find the manual page here. If after reading it you have a question, please next read the FAQ. It's kind of a pathetic FAQ file for now, but I bet your question is in it!


These are the (max. 10) most recent news items about the project:

14/12/2015-Release of version 2.3.1
Only a couple of days after putting the software on GitHub, I received my first pull request. Of course I didn't do shit with it. Nope, can't be to harsh on myself. Yes, I know it's a bit suspicious that a new release is followed so quickly after the nice acknowlegment of my work. Yeah, yeah, but this time I've got a good excuse I tell you! October 29th my son Mel Leslie was born and I can tell you he's a real time waster. Did I just say that? No of course not, he's amazing! He surely is, but with my little friend around releasing Free Software hasn't become more easy. ;)
Anyway, thank you Ark444 for your suggestion and pull request. Please again forgive me for not using your code, but your idea lives on and I thank you for that!
03/12/2015-Not a postcard, but still a pretty cool thank you, if you ask me!
"Instead of a postcard, I send you the paper we published. I know you're not a chemist, therefore, please check the acknowledgments section."
-- Bogdan Jurca

Abstract from Impact of Deactivation Phenomena on Kinetics of the C-N Coupling Reaction over Supported Cu2O Catalysts in Continuous-Flow Conditions, The Journal of Phycial Chemistry CAcknowledgments from Impact of Deactivation Phenomena on Kinetics of the C-N Coupling Reaction over Supported Cu2O Catalysts in Continuous-Flow Conditions, The Journal of Phycial Chemistry C
Now available on GitHub: jpnevulator. Patiently awaiting my first pull request. ;)
29/09/2015-Bugfix release
Both David Binderman and Rolf Freitag reported problems with the software. David correctly spotted two stupid bugs in testing if a correct integer was given to the --width and --size options and Rolf suggested to remove the calls to fcntl() and cfmakeraw() in ttyOpen(), so no longer jpnevulator will remove the parity settings made by stty(1). A new version 2.2.1 is out fixing both problems.
Those paying attention will notice the jump from version 2.1.3 to 2.2.1 and will miss version 2.2.0. You'll find it here, but it was never "officially" released. And now I'm doing total injustice to Colin Foster, who generously sended me a patch. Back in 2014 I've applied his patch, did some minor testing, asked if he would like to test it and next completely forgot about it. I'm sorry Colin, but your patch is of course part of version 2.2.1 too!
21/01/2015-Link of the day
Rolf Freitag first came up with the idea to use threads to solve the "Order of bytes broke when reading several tty devices at once" bug and next did an implementation to prove his point: If you are hunted by this bug and need a solution, maybe you can try his software as I do not see myself perform such a huge change of the software anytime soon.

Select a year and press 'See News' to see some more (old) news:

Example of the output

Below is an example of the output one can see when reading from two serial devices at the same time:

$ jpnevulator --ascii --timing-print --tty /dev/ttyS0:SB9600d --tty "/dev/ttyUSB0:Motorola MTM800" --read
2006-05-30 13:23:49.461075: SB9600d
00 00 05 3B 0D 00 00 05                         ...;....
2006-05-30 13:23:49.461113: Motorola MTM800
00 05 3B 0D 00 00 05 3B 0D                      ..;....;.
2006-05-30 13:23:49.473074: SB9600d
3B 0D 00 00 05 3B 0D                            ;....;.
2006-05-30 13:23:49.473105: Motorola MTM800
00 12 05 06 39 00 12 05 06 39 1F 00 22 80 00 0E ....9....9.."...



Please see for the latest and greatest version of the source code.


The current release of jpnevulator is version 2.3.1, which was released on December 14th, 2015. Download this compressed tarball(36.3K) and see the README and INSTALL file for more information on how to compile the program.

Older versions can be found here.

Debian GNU/Linux

jpnevulator is an official part of the Debian operating system. You can find information about it at

All the ever released packages can be also be found here.


jpnevulator is written and maintained by Freddy Spierenburg. Feel free to send questions, bugfixes and the like to

Page last modified: Fri, 20 May 2016 15:07:43 +0200
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