... INPUT GPS NMEA.183 SUPPORT2.5 INCH HARD DRIVE HR4001 stand alone DVR , digital video recorderMAX 4 VIDEO INPUT,4AUDIO INPUTGPS NMEA ... ,RECORD ON ALARM supported VEHICLE TELEMETRY,(SUCH AS SPEED,ROUTE,CAR ID,ETC) CAN BE STROED IN THE VIDEO ERRORPROOF FILE ... modeLive video, recording, playback, alarm, backup simultaneously.GPSNMEA.183 HR4001 stand alone DVR