Ptarmigan is a mobile, secure battlefield system that has been designed to improve communications reliability, capacity and interoperability. The system consists of a network of electronic exchanges or trunk switches connected by the satellite and multi-channel radio relay (Triffid) links. These provide voice, data, telegraph and fax communications. Ptarmigan also has a mobile phone or single channel radio access (SCRA), which gives mobile users an entry point to the system. Ptarmigan ensures that the headquarters have exceptional flexibility  and have trunk communications that do not impose constraints on operations.