The communication protocol defines a way for the tracking program to send commands and get responses from the tracker controller. The protocol could be as simple or as complex as possible as long as the sender and receiver understand it. Several protocols, such as EasyComm, Prosistel, Yaesu, DCU, for satellite tracking systems have been created over the years.
Several vendors of antenna rotators have published proprietary protocols, for use in their own systems. The EasyComm II protocol was chosen for this project due its simplicity and easy readability. However, the control program developed in this project has been constructed in a modular way to accommodate any other protocols without modification to the rest of the system.
The EasyComm II protocol has a comprehensive set of commands, that include passive and active commands for antenna positioning, radio frequency/mode control, generic sensor interface, and time functions. In many cases, some of the functions like radio control are duplicated in the satellite tracking program. This leaves us with only the antenna position commands - Azimuth and Elevation.
Following is a subset of the EasyComm II protocol that have been selected for implementation in this project:
In addition to these, a few system commands have been added for the convenience of the operator:
References:
Here is a list of internet resources that provide comprehensive information about the EasyComm II protocol:
AmSat
http://www.amsat.org/amsat/ftp/software/win32/wisp/easycomm.txt
QSL.Net
http://www.qsl.net/dh1ngp/onlinehelpft100/Rotator_control_with_Easycomm.htm
Ham Radio Deluxe Wiki
http://wiki.ham-radio-deluxe.com/index.php?title=Rotator_Selection