What program do you recommend for wiretapping the COM port?

Any terminal is not suitable.
There is a device that interacts with the program, I need to listen to what they are talking about.

My system winXP 64
 
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if you think so... it's your project.
tx is a single wire. You can add as many receivers as you want.
If you want to read both directions, you need two terminals. A teensy, maybe, with two uarts rx's connected to both, one to tx and one to rx...transfering both via usb to a PC. Or a just PC with two uarts (and terminals)
If you don't need both directions, a single uart (and one terminal program) will do.

it's all a pretty standard setup.

putty could be used, for example.

just have fun.
 
if you think so... it's your project.
tx is a single wire. You can add as many receivers as you want.
If you want to read both directions, you need two terminals. A teensy, maybe, with two uarts rx's connected to both, one to tx and one to rx...transfering both via usb to a PC. Or a just PC with two uarts (and terminals)
If you don't need both directions, a single uart (and one terminal program) will do.

it's all a pretty standard setup.

putty could be used, for example.

just have fun.

I just need to know what they're saying. And there you need RX and TX
Don't invent. there are programs that can listen.
 
Difficult to help with specific advice when the question is so vague, lacking detail of the hardware or application.
 
Not sure if this is what you are looking for, but this program will log a serial "conversation" between two devices to the serial monitor. Two hardware UARTs are used, as shown below.

Code:
[FONT=courier new]                          Teensy
                     [----------------]
  [ dev ]----------->[s3.rx ---> s1.tx]----------->[ dev ]
  [  1  ]<-----------[s3.tx <--- s1.rx]<-----------[  2  ]
                     [----------------]
[/FONT]

Code:
void setup() {
  Serial.begin( 115200 );
  Serial1.begin( 38400 );
  Serial3.begin( 38400 );
}

short direction = 0; // 1=RX, 2=TX

void loop()
{
  char c;
  for (;;) {
    while (Serial1.available()) {
      if (direction!=1) {
        direction = 1;
        Serial.printf( "\nRX " );
      }
      char c = Serial1.read();
      Serial3.write( c );
      Serial.printf( "%02hX ", (short)c );
      Serial.send_now();
    }
    while (Serial3.available()) {
      if (direction!=2) {
        direction = 2;
        Serial.printf( "\nTX " );
      }
      char c = Serial3.read();
      Serial1.write( c );
      Serial.printf( "%02hX ",(short)c );
      Serial.send_now();
    }
  }
}
 
If you are using a Windows PC with at least two COM ports, go to taltech.com/downloads/freesoftware & look for the link to download "Serial Breakout Box Software", a free utility which allows you to do full duplex serial analyzer style snooping. Pay particular attention to any export restrictions that may apply to your intended usage.

Mark J Culross
KD5RXT
 
If you are using a Windows PC with at least two COM ports, go to taltech.com/downloads/freesoftware & look for the link to download "Serial Breakout Box Software", a free utility which allows you to do full duplex serial analyzer style snooping. Pay particular attention to any export restrictions that may apply to your intended usage.

Mark J Culross
KD5RXT

I have one PS + uCenter program + GPS receiver. I need another program to analyze (listen) the dialogue
 
OP is looking for a Windows XP program to solve his problem –– i.e. a COM port sniffer ––, and is not interested in solutions that use a Teensy. I'd say this is the wrong forum to ask such questions.

I do recommend Wireshark (on all OSes), but do see which interfaces and protocols it supports on your OS. COM ports in Windows are not among them; WireShark won't help OP. Windows users probably want to read this before using Wireshark for USB traffic (including USB Serial adapters). For me, on Linux, Wireshark suffices for all my Teensy – Computer communications (Ethernet, USB, and WiFi), so that and PulseView are what I mostly use in this area. (PulseView is especially useful with the very cheap Cypress FX2 -based 8-channel 24 MHz logic analyzers one can get for $10 off eBay, as it then uses its own fx2lafv firmware.)
 
Code:
OP is looking for a Windows XP program to solve his problem –– i.e. a COM port sniffer ––, and is not interested in solutions that use a Teensy. I'd say this is the wrong forum to ask such questions.

Yes! I screwed up. PC of course! Windows 7 64bit.
 
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Code:
OP is looking for a Windows XP program to solve his problem –– i.e. a COM port sniffer ––, and is not interested in solutions that use a Teensy. I'd say this is the wrong forum to ask such questions.

Yes! I screwed up. PC of course! Windows 7 64bit.

The utility that I recommended in my earlier message runs on what I will call "the sniffer PC". If your setup is such that you normally connect a COM port on what I will call "the control PC" to your "device under test" (GPS, etc.), you would connect one of the COM ports on the sniffer PC to the COM port on the control PC, & the second COM port on the sniffer PC to the serial port on the device under test. With this configuration, the sniffer PC effectively sits between the control PC & the device under test. Configure the Serial Breakout Box Software appropriately for the two COM ports on the sniffer PC & it will display all data going both ways between the control PC & the device under test. I like to configure the data associated with one of the COM ports on the sniffer PC to be RED & the data associated with the other COM port on the sniffer PC to be GREEN, so I can tell a difference (by color) between the data flowing from control PC to device under test, & the data flowing from device under test to control PC. You'll need to know & properly configure the data rate that is being used between the two. You can choose between displaying the data formatted as pure ASCII, ASCII with control characters spelled out, or hexadecimal.

Note that the Serial Breakout Box Software is a Windows 32-bit app, but it runs successfully under 64-bit Windows equally well. I currently use it on a Win11Pro 64-bit laptop.

Good luck & have fun !!

Mark J Culross
KD5RXT
 
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