Common to all models are these features:
- internal GNSS receiver and antenna, 72-channels, capable of receiving GPS, GALILEO, GLONASS, and BEIDOU;
- water and weather proof enclosure to IPx6 / IPx7;
- two NMEA-0183 ports;
- NMEA-2000 port;
- small size and light weight;
- very low power consumption;
- TNC connector for external GNSS antenna if needed;
- FlexFit mounting bracket;
- USB connector for interface to computer terminal, and
- silent mode switch for receive-only operation.
There are two branches of the B900 series: 2-Watt Class-B Carrier Sense devices, and 5-Watt Class-B Self Organizing devices. In each branch there are: a base model; a model that adds WiFi, Bluetooth (BT), and a voyage data logger; a model that adds an internal antenna splitter; and a model that adds WiFi, Bluetooth, a voyage data logger, and internal antenna splitter. Here are the model designators and MSRP in US dollars:
2-Watt Carrier Sense CSTDMA
B921 base model = $499
B922 + WiFi/BT + voyage data logger = $699
B923 + Antenna Splitter = $649
B924 + WiFi/BT + Antenna Splitter + voyage data logger = $899
5-Watt Self Organizing SOTDMA
B951 base model = $599
B952 + WiFi/BT + voyage data logger = $799
B953 + Antenna Splitter = $749
B954 + WiFi/BT + Antenna Splitter +voyage data logger = $999
The GNSS receiver can receive any two GNSS systems simultaneously, and three systems can be received simultaneously if two are GPS and GALILEO. The GNSS receiver sensitivity is said to be very good, and em-trak does not expect that an external antenna will be needed if the unit is mounted on deck or under a fiberglass deck, or inside a helm console on an open boat.
The optional internal antenna splitter allows the AIS transponder and a VHF Marine Band radio to share a common antenna. The shared antenna must be an antenna with a wide VSWR bandwidth that can work at both 156-MHz and 162-MHz.
Both NMEA-0183 ports have TALKER and LISTENER balanced pairs. The primary port uses the recommended NMEA wire insulation colors to aid in identification of the signals. The baud rate is 38,400-bps. The second port uses an alternate set of wire insulation colors to distinguish it from the primary port, and it operates at 4,800-bps. The NMEA-2000 port is provided on the standard DeviceNET Micro connector.
The average power consumption of models without the optional antenna splitter ((B921/B922/B951/B952) is only 0.17-Ampere or 1.6-Watts at 12-Volts. The models with the antenna splitter (B923/B924/B953/B954) consume slightly more average power, 0.28-Ampere or 2.1-Watts at 12-Volts.
There is a 12-pole connector for attaching the wiring harness to the device for power, the two NMEA-0183 ports, and the Silent Mode switch. The wiring harness is 2-meters long.
Models with the optional antenna splitter add a second SO-239 connector. A 1-meter cable for connecting to a VHF Marine Band radio is also supplied.
The configuration of the B900 series is accomplished with a software application, proAIS2. Versions of proAIS2 are available for both WindowsOS and MacOS. A computer-to-B900 connection can be made using a USB port and a micro-USB cable. The required cable is not supplied but is widely available. In the USA, the B900 devices will be delivered from the dealer with pre-configured settings for the MMSI and other data (such as CALLSIGN, VESSEL NAME, and dimensions of the offset of the GNSS sensor in the hull).
The models with WiFi and Bluetooth can connect to a smartphone using the CONNECT-AIS application, available for Google smartphones and Apple iOS devices. This application also be used for configuration of the B900 device.