Free pickup point from €150 in France
Pickup at Skysat possible

Custom installation

Trust Skysat to install the equipment on board

Request a quote

Installers near you

thanks to our network of approved installers

Find an installer

Support service

Opt for additional installation assistance

Save 4%

EM-Trak

MCT-EMTR-B921

B921: Class B AIS transponder CSTDMA 2W USB-NMEA0183-N2K

The EM-Trak B921 Class B AIS transponder is a CSTDMA 2W maritime safety solution, integrating a multi-constellation GPS receiver and USB, NMEA 0183, and NMEA 2000 interfaces for extended connectivity. Water- and weather-resistant (IPx6 and IPx7), it provides reliable visibility and easy integration with your navigation system.

It is supplied with a power and data cable, an external GPS antenna, a FLEXI-FIT mount, a user manual, and a quick-start guide.

Retail priceBenefit from the professional rate

533,45€

533,45€ ~~557,50€~~

Shipping calculated at checkout.

Prices shown excluding VAT for United Arab Emirates. If your delivery address is in the European Union, the VAT of the destination country will be added at checkout.

Available in stock

Free pickup point from €150 in France
Pickup at Skysat possible

Custom installation

Trust Skysat to install the equipment on board

Request a quote

Installers near you

thanks to our network of approved installers

Find an installer

Support service

Opt for additional installation assistance

Detailed description

The EM-Trak B921 Class B AIS transponder provides a maritime safety solution for navigation, allowing your vessel to be visible to other AIS-equipped boats and to detect their positions. Designed for easy integration, it uses CSTDMA (Carrier Sense Time Division Multiple Access) technology with a 2 W transmit power.

Extended connectivity and simplified integration

The B921 features NMEA 0183 interfaces (4,800 and 38,400 baud) and NMEA 2000 (LEN=1), along with a USB port, ensuring compatibility with most chartplotters, sensors, and modern navigation systems. This versatility facilitates AIS data exchange and conversion of NMEA PGNs between different protocols. An integrated 72-channel GPS receiver, compliant with IEC 61108-1, supports L1 GPS, GLONASS, Galileo, and BeiDou bands for precise positioning.

Robust design and technical performance

With compact dimensions of 149 x 118 x 47 mm (L x W x H) and a weight of 320 g, the B921 fits discreetly aboard. It is water- and weather-resistant, meeting IPx6 and IPx7 protection ratings, making it suitable for demanding marine environments. Its power supply is compatible with 12–24 V DC systems (maximum range: 9.6 to 31.2 V), with an average power consumption of 135 mA / 1.65 W at 12 V and a peak current of 2 A. The transponder operates within a frequency range of 156.025 to 162.025 MHz with a 25 kHz step, delivering a CSTDMA output power of 33 dBm ± 1.5 dB. It includes LED indicators for power, transmission status, errors, and silent mode.

Configuration and additional features

The transponder can be configured via a PC using the proAIS2 tool or via a smartphone. The silent mode, which can be activated via configuration tools or an external switch, disables transmissions from your own vessel while continuing to receive position reports from other boats—useful in situations requiring discretion.

Documentation

Type	Nom
	EN - Manuel utilisateur - EM-Trak gamme B900 (B921-B954)
	FR - Manuel utilisateur - EM-Trak gamme B900 (B921-B954)
	EN - Guide de démarrage rapide - EM-Trak gamme B900 (B921-B954)
	EN - Déclaration de conformité - EM-Trak B921

Expert opinion

« Analyse technique de l'AIS EM-Trak B921 : Sécurité et intégration polyvalente »

Le transpondeur AIS EM-Trak B921 se positionne comme une solution essentielle pour la sécurité des navires de plaisance et des petites embarcations commerciales. Sa classification en Classe B CSTDMA, avec une puissance d'émission de 2 W, assure une détection efficace par les navires environnants équipés d'AIS, sans les contraintes réglementaires et de coût des systèmes de Classe A.

L'un des atouts majeurs du B921 réside dans son récepteur GPS multi-constellations intégré (GPS, GLONASS, Galileo, BeiDou). Cette caractéristique simplifie grandement l'installation, utilisant une antenne GPS externe dédiée fournie et réduisant les points de défaillance potentiels. La redondance des systèmes de positionnement garantit une acquisition de signal rapide et une précision accrue, même dans des conditions de réception difficiles.

En termes d'intégration système, le B921 offre une flexibilité remarquable grâce à ses multiples interfaces : NMEA 0183 (à la fois haute et basse vitesse), NMEA 2000 et USB. Cette connectivité complète permet une intégration transparente avec une large gamme de traceurs de cartes, d'écrans multifonctions et d'ordinateurs de bord, qu'ils soient anciens ou plus récents. La conversion des PGN NMEA de 2000 vers 0183 est un avantage significatif pour les installations existantes ou hybrides.

Sa robustesse, attestée par les indices IPx6 et IPx7, garantit une résistance aux embruns, aux projections et à une immersion temporaire, ce qui est crucial pour un équipement installé dans un environnement marin. La configuration est également facilitée par des outils logiciels compatibles PC et smartphone, offrant une grande souplesse pour la mise en service et la gestion des données du navire. C'est un choix judicieux pour tout propriétaire de bateau souhaitant améliorer sa visibilité et sa connaissance situationnelle en mer avec une solution fiable et facile à intégrer.

Payment and security

Your payment information and data are processed securely.

B921: Class B AIS transponder CSTDMA 2W USB-NMEA0183-N2K

533,45€

533,45€ ~~557,50€~~

Frequently Asked Questions

Need help? Contact us

What is a Class B CSTDMA AIS transponder?

An AIS (Automatic Identification System) Class B CSTDMA transponder is a maritime safety device that enables your vessel to be visible to other AIS-equipped boats and to detect their position. The CSTDMA (Carrier Sense Time Division Multiple Access) technology is used for data transmission, with a transmit power of 2 W. Class B transponders transmit at a lower power and reporting rate than Class A units, making them generally more affordable while still providing essential safety functionality.

What are the dimensions and weight of the EM-Trak B921 AIS transponder?

The EM-Trak B921 AIS transponder has compact dimensions of 149 mm (length) x 118 mm (width) x 47 mm (height). Its weight is 320 g for the transceiver-only variant.

What connectivity options are available on the AIS transponder B921?

The AIS transponder B921 offers several connectivity options for easy integration with your navigation systems:

NMEA 0183: Two NMEA 0183 ports (one high-speed 38,400 baud and one low-speed 4,800 baud) for connection to chartplotters and other sensors.
NMEA 2000: One NMEA 2000 port (LEN=1) for integration into NMEA 2000 networks.
USB: One USB port for connection to a PC for configuration and data visualization.
Note that the B921 model does not include Wi-Fi or Bluetooth features, which are available on other variants in the B900 series (B922, B924, B952, B954).

What is the required supply voltage for the AIS transponder B921?

The AIS transponder B921 requires a DC power supply of 12 to 24V, with a maximum operating range of 9.6 to 31.2V. Its average power consumption is 135 mA / 1.65 W at 12V.

Is the B921 AIS transponder waterproof?

Yes, the AIS transponder B921 is designed to be water- and weather-resistant. It is certified to IPx6 and IPx7 standards, ensuring protection against powerful water jets (IPx6) and temporary immersion (IPx7).

Does the AIS transponder B921 have an integrated GPS receiver?

Yes, the AIS transponder B921 integrates a 72-channel GPS receiver. This receiver complies with IEC 61108-1 and supports the GPS L1, GLONASS, Galileo, and BeiDou bands, ensuring accurate and reliable positioning for AIS transmissions.