Guys, I did some testing on my T200 to figure out the whole serial port wiring issue.
Test 1: 1. Write a test application to open the serial port on the PC with DTR/DSR and CTS/RTS disabled 2. Go to TELCOM on the T200 3. STAT 98N1ENN 4. TERM 5. Press any key on the T200 and it freezes. Test 1: 1. Write a test application to open the serial port on the PC with CTS/RTS disabled but DTR/DSR enabled 2. Go to TELCOM on the T200 3. STAT 98N1ENN 4. TERM 5. Press any key on the T200 and it freezes. Test 3: 1. Write a test application to open the serial port on the PC with CTS/RTS enabled but DTR/DSR disabled 2. Go to TELCOM on the T200 3. STAT 98N1ENN 4. TERM 5. Press any key on the T200 and all data is sent to the PC and sent back to the T200. Works perfectly. I Then tested to see if TELCOM is actually using RST/CTS. For this I wrote a small application to send a large file to the T200 with Xon/Xoff turned off. I then put a bit of code in place to see if the RTS/CTS flags were ever changed by the T200 to tell the PC to stop sending. What I found was that the T200 never sent a flag to the PC signaling to pause sending data due to the buffer being full. This caused garbage on the screen. So, what I can conclude from all of this is that the T200 serial port hardware MUST have the RTS/CTS active or it will freeze the hardware. But the TELCOM application does not use those signals to halt data transfer when the buffer is full. Instead it relies on Xon/Xoff. Hope that clears things up a bit on the mystery of the T200 serial port. Kurt
