Last updated: 12 July 2020 with minor text changes
As we understand it, there were basic three types of control technology created to meet the specific requirements by the end user. The technologies included a FSK mode, a serial data mode, and a mode specific to Rockwell-Collins called "Modulo 2" (most commonly seen in the 718 or AN/ARC-174 series).In addition, there was a variation called "biphase" used in the URG-II systems. This version used a carrier frequency of 4800 Hz that had its phase shifted to change state. It required a clocking carrier also at 4800 Hz. The return channel that carried system status was also based on the same system. The control word format for the biphase mode in the URG-II is defined from the actual documentation from the URG-II project. It can be found here Much more on this topic to come. In addition, we hope we can show how we created a web based User Interface to control a FSK based system.