Garmin VHF 215 AIS Technical Reference for Garmin NMEA 2000 Products - Page 12

NMEA 2000 power Backbone extension cable In-line terminator To the final NMEA 2000 device on this side of the backbone NMEA 2000 Cable Length and Device Limitations When building your NMEA 2000 network, consider these limitations: • The distance between any two points on an NMEA 2000 network must not exceed 100 m (328 ft). To estimate this distance, measure between the terminators on your backbone and add the length of the drop cable for the devices connected to the T-connectors at the ends of the network. • The total length of all drop cables cannot exceed 78 m (256 ft). • The maximum length of a single drop cable from the top of a T-connector to NMEA 2000 device is 6 m (20 ft). • No more than 50 NMEA 2000 devices can be connected to an NMEA 2000 network. Considerations for Existing NMEA 2000 Networks If a boat has an existing NMEA 2000 installation, and you would like to add Garmin NMEA 2000 equipment, you should observe these considerations. Cable and Connector Type: Garmin uses NMEA 2000 micro connectors for all cables and connectors. An existing NMEA 2000 network may use NMEA 2000 mini connectors and cables in the backbone. Mini connectors are larger than micro connectors, so you must use a converter or adapter to connect a Garmin NMEA 2000 device to a backbone with mini connectors. Power: You must determine whether the existing NMEA 2000 network is connected to a power source, because an NMEA 2000 network must connect to power to function correctly (Power Connection Considerations, page 7). If you must connect power to the NMEA 2000 network at more than one location, you must install a power isolator in the backbone between the two power connections (Power Isolation, page 10). Termination: You must determine whether terminators are installed on the ends of the existing NMEA 2000 backbone, because anNMEA 2000 network must be properly terminated to function correctly. You must not add more terminators to an NMEA 2000 network if it is already properly terminated. If you are unsure of any of these considerations, you should contact your boat manufacturer or a certified NMEA 2000 technician for assistance. General NMEA 2000 Data Types Every NMEA 2000 certified sensor provides unique information to NMEA 2000 certified display devices on the NMEA 2000 network. The data you can view on your display device depends on the sensors you have installed and configured. Refer to the following table for a list of data types that you can view on a display device; specific NMEA 2000 PGN information required to view or calculate that data type; and the NMEA 2000 sensor that typically provides required PGN information. In some cases, more than one sensor is necessary or a specific combination of sensors may provide more precise information. 12