title: Grabbing traffic from COM
body: <p>I need to grab traffic from COM port under <strong>MS-DOS</strong>.</p>
  
  <p>I found program <strong>ComSpy</strong> (which must grab data from COM port and send to prn, do it in TSR), run it, run <strong>prn2file.exe</strong> and run analyzed program, but it did not logging.</p>
  
  <p>Is it possible to write a memory-resident program (<strong>MS-DOS</strong>) to get all traffic from COM port and log to file, but without interfering with other program (which communicate with com port(work with com by interrupts))?</p>