Here is the wiring of a serial interface
http://www.mindspring.com/~n2wwd/html/body_doppler_compensation.html
For usb to TTL you need 5V TTL logic and presumably similar connections and baud rates.
If you look on ebay you can see people selling them and the rig end needs the right connector, a 6 pin DIN.
You connect the TX of the USB lead to the RX on the radio (pin3) and the output of the rig (pin 2) to the RX on the USB converter and pin 1 to ground.
You probably don't need the pin 6 connection as the converter will be supplied by the USB power.
Make sure to get a USB cable with drivers available for your current operating system and ideally a common one so that drivers will be available in many years time for future systems.
Ideally if you could afford it a fully isolated interface would be better.
On 23/03/2015, ingejack@cox.net ingejack@cox.net wrote:
Need to know what USB cable that FT736R users are using to connect their computer and SATPC32 with. It calls for a RS232 TTL cable but need to know what company and cable descrition they are using if possible., Thanks for any help !! Jack/KC7MG