 Buffer |
 Multiplexer / Combiner |
 Autoswitch |
 Gateway |
 Converter |
NMEA2000 |
NMEA0183 |
 NMEA2000 cables & accessories |
NMEA Buffer
NMEA Buffer amplifies a weak incoming signal from talker device. Amplified signal can thus be distributed to many listener devices which otherwise would cause too much load for weak talker device.
In addition to amplification, a buffer can offer protection for NMEA equipment from harmful electricity. Typically the talker device is opto-isolated from listener devices. Further on different listener devices can be isolated from each other thus providing a complete protection and isolation to certain level of harmful electricities.
Quite often limited buffering feature is included to various NMEA processing equipment but always this is not enough and then a specific NMEA buffer is highly recommended.
NMEA Combiner/Multiplexer
NMEA Multiplexer combines incoming data streams into one output data stream. Basic level of multiplexing requires similar data streams (for example 4800bps each) on the input side and the output is a sum of input streams at same port speed (for example 4800bps).
Multiplexer is typically used when listener device has only one input port but two or more data streams are required to interface with it. This situation occurs in almost every navigation system even in leisure boating.
NMEA Combiner is an advanced multiplexer. Combiner does not care about the port speed of each incoming signal. It can easily be programmed to cope with different port speed simultaneously and even output can have different speed.
Other features of combiner are the ability to filter unwanted senteces from input streams and the use of priorities in input ports.
NMEA Autoswitch is an automatic switch that has an ability to choose always the best quality signal from multiple input streams. This feature is used typically in situations where some level of redundancy is required (for example two devices sending GPS information but only the other can be accepted for navigation at the time). Other use is when for some reason two devices are sending same NMEA sentences like GPS compass and GPS or compass.
NMEA Gateway is a protocol converter that is able to read the sentences of one protocol and convert the contents of those sentences to other protocol. Typical example of this kind of a product is NMEA0183 - NMEA2000 gateway where NMEA0183 is an old RS422, ASCII based point-to-point protocol and NMEA2000 is modern CAN bus binary based point-to-multipoint protocol.
NMEA Converter is a media converter or electrical protocol converter that can convert signals from one electrical level to another. Typical conversions are between RS232-RS422, RS232-RS485, RS232-USB, RS422-USB, RS232 can be converted to Ethernet as well.Converter can add a level of protection and isolation between converted signals. This is becoming more and more important while PCs with totally unprotected USB ports are interfaced with shipboard navigation system with unknown electrical interferences.
