Read data from a serial port to USB in Ubuntu using C++

Question

I have a GPS that has a serial port, and it has a transfer cable from serial to USB. It is connected to the laptop through USB, and is transmitting data in Hex. I want to use this data in my C++ code on Ubuntu. Any ideas where could I start, and how I could manage to read the data?

Solution

Start by opening a file (fstream, FILE * or OS handle) to "/dev/ttySn" where n is the number of the device, then read away.

#include <string>
#include <fstream>
#include <iostream>

std::string str; 
std::fstream f; 
f.open("/dev/ttyS0"); 
while (f >> str)
{
   std::cout << str;
}

That should "echo" out the contents of ttyS0 - that may of course be the "wrong" port for your device, but if you know where it is connected that should do the job. You may also need to set the configuration of the port. For example, using the stty command - baudrate would be the most important, so something like stty -F /dev/ttyS0 19200 will set the baudrate (actually bitrate) to 19200 bits per second. Most other parameters are probably ok.

Comments

[Richard Chambers]

See this stack overflow on setting up the connection stackoverflow.com/questions/5347962/…

[Richard Chambers]

And then this one on reading and writing the device stackoverflow.com/questions/5014451/…

[dbasnett]

And you can help us help you by posting the exact manufacturer and model of the GPS.

[Zeyad]

navilock.de/produkte/G_60109/merkmale.html?setLanguage=en this is the exact GPS we are using here.

[Lightness Races in Orbit]

It's not "transmitting data in hex". It's transmitting data in some encoded binary form like all computers do - you're just looking at the values in hex.

[Zeyad]

Thank you. I have a second question how do I know the port of the device ?

[Mats Petersson]

I have no idea. Try having a look in dmesg or something to find which port the kernel gives it when you plug your USB serial port in.

[Lightness Races in Orbit]

I've corrected Mats's answer; probably no need for this now