The Brookhouse eMux

Integration of NMEA 0183 server and on-board wifi network

After the introduction of the Brookhouse iMux in 2010, the new Brookhouse eMux now takes NMEA 0183 over wifi a  step further with integration of NMEA 0183 and on-board wifi networks. 

Navigation with iPads and other i-devices has come of age. Oceans have been crossed with the iPad as the main navigation tool, receiving instrument data from the iMux via wifi. Today we find that many vessels, not only super-yachts or commercial vessels, have on-board wireless networks with  (3G) routers for internet access in coastal areas while under way, on anchorages and in harbour. 

The Brookhouse eMux makes good use of the local network and wifi capabilities of the router, also  when the vessel is out of range of  cellular service. Installation of a router on board is worthwhile even if cellular service is never used.  A reliable, feature-rich, on-board wireless network can be created at low cost, which is ideally suited for integration of  multiple iPad use with the boat's instrument network.  

The Brookhouse eMux interfaces directly to the router via a reliable RJ45 ethernet cable connection. NMEA 0183 GPS, AIS and other instrument data is combined by the multiplexer/server in one data-stream and is available to network users.  iPads, iPhones and laptops can receive the data simultaneously via wifi. One of the clients can also control the auto pilot for track-mode steering to a waypoint or along a route and waypoints can be transferred to other network clients or a chart plotter. The eMux also has a serial port for connection of a chart plotter or computer. 


Benefits and features 

  • iPads, iPhones, Androids and computer,  can access the boat's NMEA instrument network via the same on-board Access Point (SSID) with same settings as for Internet access via 3G.

  • Reliable RJ45 ethernet connection of the eMux to the router.

  • All the rich features offered by the router, including security/encryption can be used to access navigation data.

  • In most cases the eMux can be installed without complicated configuration.

  • The router can be easily configured from an iPad or computer, by accessing its internal configuration web page.

  • Vessel tracking

Advantages of using a router's 3G internet access as opposed to individual cellular access by each iPad/iPhone.

  • Superior signal quality for all users  as result of high gain aerial and booster (if installed). On anchorages or in remote harbours with poor 3G signal quality, direct access by iPad-3G or other devices to cellular data services may be very slow, intermittent or impossible. 

  • One SIM card in router only, iPads/iPhones, computers and Androids share access. When visiting foreign harbours  one (prepaid) SIM card can be purchased, only for the router. This will provide  local cellular internet access for all on-board users. 

  • Wifi-only iPads, i.e. iPads or other tablets without 3G capability, can be used for 3G cellular internet access via router.

  • If the router is a model  with analog telephone connector, voice calls can be made via the router, with the benefit of the superior signal quality provided by the marine aerial and booster (if installed). 

The standard eMux NMEA server combines GPS and NMEA 0183 instrument data from three 4800 baud ports with AIS receiver or transponder data from a 38400 baud input port. The combined data stream is transmitted  via TCP/IP over an RJ45 ethernet cable to a router.  The eMux also has a serial output port for a hard-wired connection to a chart plotter and/or a computer. NMEA data received back via TCP/IP is output from the eMux NMEA OUT port at 4800 baud for auto pilot control in track mode or for waypoints transfer. All of the functions of the Brookhouse multiplexer model AIS including filtering and NMEA sentence editing on the fly are available in the eMux.   

The eMux-ST model (as in the diagram above) offers the same features as the standard model, and in addition Raymarine Seatalk protocol is converted to NMEA 0183. If the Seatalk port is enabled (by default for model ST) 3 of the 4 NMEA input ports can be used.  The Seatalk port can also be disabled in the setup-menu. In this case all 4 NMEA ports are available, and the unit's functionality is identical to the standard emux.

The eMux is easy to install, no configuration is necessary unless the advanced features need to be enabled.

iMux or eMux?
The main differences between the two is the  wifi communication and the supported number of simultaneous users. The iMux has its own internal wifi module while the eMux delegates the wifi task to a router, and is connected to the router via a cable.  As a consequence, the eMux can stay connected to the same AP (the router) for both navigation and access to the internet via 3G. 

The multiplexer part of the iMux and eMux is identical.  

Specifications standard eMux

  • 4 opto-isolated “NMEA Listener” (Input) ports, 3 at 4800 bps, 1 at 38400 bps for AIS.

  • 1  RS232 output port  for connection to a chart plotter or computer

  • 1 RS232 input port 
    (baudrate conversion input).

  • 1 Output RS422 port (differential NMEA talker port) 4800bps
    (baudrate conversion output)

  • 1 RJ45 port for connection to a router or computer ethernet LAN port.

  • Baudrate conversion 38400bps-4800bps.

  • Indicators: red LED for power, green LED for data-transmission.

  • Supply Voltage: DC 9-35 Volts.

  • Reversed polarity protection.

  • Physical size: 110x65x37mm (hxwxd)

  • Weight: 140 grams

  • Mounting: bulkhead mounting with screws.

  • NMEA management and control:

    • NMEA Sentence Filtering

    • NMEA Sentence editing “on the fly” for NMEA protocol conversion.

    • Automatic port switching.

Specifications eMux-ST

Specifications are the same as for the standard model with 2 exceptions:

  • Instead of 3 NMEA 4800 input ports the eMux-ST has 1 Seatalk port and 2 NMEA 4800 baud input ports. If the Seatalk port is disabled, a 3rd NMEA input @ 4800 is available.

  • Seatalk GPS data, if available, is always sent to the 4800 NMEA output port as input for a DSC radio.

    *All popular AIS receivers and transponders are supported.


Pricing, ordering and payment 



Note: Seatalk is a trade-mark of RayMarine.




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