ViLX-OSA Lexicomm Surface Type A Fire TelephoneViLX OSA Lexicomm Surface Type A Fire Telephone These are primarily for use by the fire services in high rise buildings, to provide clear communications between the control point and the fire fighters, as radio systems may not work. They are typically located in fire fighting lift lobbies, but may also be used by fire wardens, or by stewards and marshals in sports venues. The handset is fully monitored and robustly constructed.