Overview Mode 4 Interrogator System (M4IS) provides host systems with the ability to perform Mode 4 interrogations on the TPS-75 radar. The system supports multiple protocols and both serial and IP formats. It also supports interrogations from multiple hosts. It has been successfully tested by the 133rd TS and fielded.   The M4IS-101D accepts mode 4 interrogation requests from a host computer system and closes the TPS-75 mode 4 override circuit to trigger interrogation. The M4IS uses the start and stop azimuths in request messages and the history of northmark arrivals from the TPS-75 to determine the start and stop time for requested interrogations.   Details M4IS simple (TCP/IP-UDP) M4IS simple (Synchronous serial) FPS-117 CD-2 (Synchronous serial) TPS-75 Radar Interface Rack mountable Supports queries from multiple hosts Provide radar plot interface to host as well as interrogation requests to radar ASTERIX interface to host Provide status/error information to host Support for additional radar types Download the Mode 4 brochure here.