em-trak B923 AIS Transceiver wiring diagram

B923 is a 2 W CSTDMA Class B AIS transceiver with an integrated VHF antenna splitter. The neighboring B924 adds wireless interfaces; the B923 does not have Wi-Fi or Bluetooth. Its shared antenna connection can serve both AIS and a compatible VHF radio, using the distinct antenna and radio ports shown in the manual.

Use red positive and black negative on the power/data harness, with the specified 3 A fuse block or suitable circuit protection. The transceiver accepts 12/24 V supplies within a 9.6–31.2 V range. Its NMEA 2000 connection must still be on a 12 V network: that port neither powers the transceiver nor accepts a 24 V backbone.

The exact-model specification gives B923 an average 245 mA / 2.95 W at 12 V and a 2.5 A peak. An earlier general paragraph gives a lower family average, so the catalog deliberately uses the B923 row. The peak field represents transmit pulses, not measured startup inrush. Cable sizing must support those pulses without voltage collapse. Terminal bounds are based on the 3 A protection, not a claimed connector ampacity. USB alone is for configuration and does not provide normal AIS transmit or receive operation.

Use a marine VHF antenna suitable for the splitter variant and its specified frequency range. Connect the VHF radio to the radio socket, not the antenna socket. Keep coaxial connections dry and provide bend and strain relief. Select a mounting position with usable GNSS reception or install the correct external GNSS antenna, retaining visibility of the status LEDs.

NMEA 0183 port 1 is the high-speed AIS path at 38,400 baud; port 2 is the slower 4,800-baud sensor path. Alternatively, use a Micro-C drop on a correctly terminated NMEA 2000 backbone. Match the destination interface rather than joining same-colored wires across brands.

Configure static vessel details with the supported proAIS2 procedure and verify MMSI, dimensions and antenna position before writing them. MMSI entry is intentionally restricted; a wrong saved identity needs the manufacturer's support procedure. Follow the regional programming requirements in the manual.

With normal DC power and antennas connected, check GNSS lock, status LEDs and received targets. Silent mode still receives but suppresses your transmissions; verify it is not selected when you expect to be seen. A remote internet AIS map is not a dependable immediate commissioning test. Diagnose local antenna, GNSS, supply and configuration status first.

Manufacturer B900 manual, distributor-hosted PDF, printed pp. 11–12 (variant matrix), 17–18 (harness/protection), 21–24 (configuration/network), 29 (silent mode), 35 (exact-model power). Official B923 page confirms identity. The original attachment link had moved; the mirror and hash are documented in the ledger.