B&G NAIS-400 Class B AIS Transponder System

B&G NAIS-400 Class B AIS System with GPS-400 Antenna (NAIS-400)

The B&G NAIS-400 is a compact, black-box Class B AIS (Automatic Identification System) Transponder designed to enhance situational awareness and collision avoidance for cruising and racing sailors. Operating across marine VHF frequencies, the NAIS-400 automatically transmits key vessel data—including vessel name, call sign, position, Course Over Ground (COG), and Speed Over Ground (SOG)—to surrounding vessels equipped with AIS, while simultaneously receiving target data from Class A and Class B traffic.

Supplied with a dedicated GPS-400 external GPS antenna, the NAIS-400 provides high-accuracy, real-time position fixes required for strict AIS transmission standards. Featuring multiple interface options—including NMEA 2000®, NMEA 0183®, and USB—the unit integrates seamlessly with B&G Vulcan, Zeus, and Triton displays, and includes a low-power "Silent Mode" function to suspend transmissions while retaining full target reception during tactical racing or offshore passages.

Key Features

• Class B AIS Transponder: Transmits vessel identification and navigation metrics while receiving target position data from nearby vessels.

• Included GPS-400 Antenna: Supplied with a dedicated external GPS antenna to ensure precise spatial locking and timing for AIS slot transmissions.

• Multi-Protocol Connectivity: Features NMEA 2000®, NMEA 0183®, and USB connections for universal integration with chartplotters and PC navigation software.

• Silent Mode Control: Allows operators to disable the AIS transmitter via display control or a remote hardware switch for stealth or privacy while continuing to monitor surrounding targets.

• Compact & Low Power: Lightweight, IPX7 waterproof housing with low current draw (< 2 W average) suitable for sail and power vessels.