Garmin GDL 88 User Guide - Page 15

2.3 Traffic Information Service - Broadcast (TIS-B) TIS-B provides the bridge between the current, radar based, ATC system and the future ADS-B based system. When an ADS-B In or Out capable aircraft is within the service volume of an FAA ADS-B ground station, the ground station will begin to broadcast a portion of the ATC radar picture to the aircraft. This aircraft is then included in the list of aircraft that is being provided TIS-B service and is then considered a "TIS-B participant." ATC radar tracks for other aircraft within ±3,500 feet and 15 NM of the participant will be provided by the ground station, to include altitude, position, ground speed, and ground track. TIS-B data is broadcast once every three to thirteen seconds depending on the characteristics of the radar providing the data to the ground station. Figure 2-5 TIS-B Operation - FAA Illustration NOTE: Even if the display is showing TIS-B traffic, unless the TIS-B participant indication is present (see Section 2.1) , TIS-B services are not being provided specific to your aircraft and the traffic picture may not be complete. 190-01122-03 Rev. A GDL 88 ADS-B Transceiver Pilot's Guide 2-5