Navtel 9460 Protocol Analyzer info?

These programs tend to need a PC with 2 serial ports. You want to monitor the data flowing over the 2 data lines in then link between the 2 devices you're investigating, so you need 2 serial inputs on the monitoring device (== PC). Typically you link the TxD line of the cable between the 2 devices to the RxD line of one of the serial ports, and the RxD line of the cable to the RxD line of the other serial port. Handshake lines are done similarly (if they're monitored at all). For example, the CTS line of one of the serial ports could monitor the RTS line of the cable, the CTS line of the other port could monitor the CTS line of the cable. You don't use the output lines on the PC serial ports at all. I seem to remember there was a project in Elektor magazine some years ago to make such a cable, which worked with one of the 'stnadard' monitoring programs. Don't ask me which progrma or to find the article, though. -tony