With the current resurgence of Packet Radio I decided to dust off my old Packet Radio Terminal Node Controller (TNC). There were untold thousands of these made in the late 80's and early 90's and to this day can be found at junk sales and hamfests for very modest prices.
One of the issues facing us today is that these modems typicaly used an RS232 serial port to communicate with the host computer. Take a look at your computer. Do you have an RS232 port? Most likely not. They have gone the way of the printer port and the dinosaur. Everything has moved over to USB.
The upgrade is very easy requiring only a USB-TTL interface commonly used to program the Arduino and other like microprocessors. The interface connects to the TTL facilities on the rear of the TNC.
The wiring is trivial. Using some female DuPont connector wires connect the 2 devices together as follows...
USB TNC
GND -------------------- GND
TX -------------------- TX
RX -------------------- RX
Set up your terminal program to reflect the port and speed settings reqired by your TNC then turn it on.
