On 6/8/05, Koenraad Lelong wrote:
Hi, I'm writing an application that uses a serial port. I am using some kind of driver, but I'm not getting the expected results. So I would like to see what is written to and comming from the serial port. Since I use Ethereal to transparently snif the network, so I wonder if there exists something like it for the serial port. I googled and the only thing I thought usable was 'cat /dev/ttySx > data.dat &' but when I tried this the filesize was only one byte although there were sent and received many more. Is this usable for binary information ? For receive AND transmit ? Any suggestions are welcome ! Thanks. --
Koenraad, I have used several rs-232 monitors (sniffers) over the last 15 years. During that time I have tried several that run on the same PC that is sending/recieving the traffic and I have not found any that don't introduce problems (if they work at all). (My experience with serial monitor linux drivers is very limited, so you may find something that works.) I have been very happy with several external monitors. Typically they use a seperate monitor PC with 2 com ports. Then a special 4 headed serial cable is used to allow this computer to monitor all the traffic on the serial line. The cable should be included with any purchased software, or a pinout provided of it is GPL software. The monitor computer should not be a store and forward device. It should be purely passive and the communication still work even if it is off. This is accomplished by having _only_ the incoming pins of the 2 com ports wired. One of the com ports is used to listen (and listen only) to the data / pins coming out of your device. The other com port is used to listen to the data / pins going into your device. By doing the above, the communication path is totally unaffected by the monitor and you can be assured it is not introducing any anomolies. Greg -- Greg Freemyer The Norcross Group Forensics for the 21st Century