Navitron
Systems Ltd
Heading & Speed Data Interface
Type NT925HDI

BSH Type Approved for stand alone (independent system) use with azimuth tracking units of all kinds (radars, trackplotters, antenna alignment systems, nav computers etc.) and Wheelmark approved for use with Navitron NT921G/NT951G/NT990G and NT991G MK2 autopilot systems, the NT925HDI (Heading Data Interface) provides four types of simultaneous output data converted from virtually any synchro or step by step gyrocompass heading outputs.

In addition, NT925HDI units incorporating software version 2.0r and later, will accept 200 or 400 pulses per nautical mile from speed log systems and will provide NMEA output data in heading only, speed only or combined speed and heading formats as required by ECDIS and AIS Systems etc. Version 3.0 software and later also provides Rate of Turn (ROT) NMEA data outputs.


On receipt of gyro heading signals, all four data types are simultaneously and continuously transmitted on the relevant output channels which are opto isolated to eliminate common mode complications.

When speed input data is available (200 or 400 pp.nm) combined speed and heading data is also available from the NMEA output channels (VHW sentence)

Gyro heading data is permanently displayed on the NT925HDI via a 4 digit LCD with variable red backlight illumination for night viewing and built in alarm functions warn of gyro input and / or NMEA output data failure.

An internal power monitor relay provides a volt free normally open (NO) or normally closed (NC) contact to warn of power supply failure (contact ratings 0.5A @ 125Vac, 1A @ 30Vdc).

Suitable for 11 - 40Vdc power supply connection, the NT925HDI can be powered up directly via its panel mounted ON/OFF switch or from a remote location via remote power up terminals provided.

NT925HDI Technical Specifications

Heading & Speed Data Interface Leaflet Download (PDF)

Click for the NT925HDI PDF Manual


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