Network Backbone and Network Nodes
A network bus backbone consists of network cabling, terminators and T connectors. Network nodes are made by fitting
Staying with the previous phone wiring example, T connectors on the backbone are the equivalent of phone jacks spread throughout a house. To pick up a phone and be able to hear a conversation from another phone in the house, both phones have to be connected to the main phone line. In similar fashion, only sensors and display units plugged into the NMEA network can share information. The network backbone is like the phone wiring that runs throughout a home.
It connects the network nodes, allowing them to communicate across the network. Connections found in the middle of the bus could have T connec- tors or backbone network cable plugged into one or both sides.
Connections at the end of a network will have the backbone cable plugged into one side and a terminator plugged into the other, as shown in the fol- lowing figure.
|
| Backbone cable | |
Terminator at | Double T | (to rest of bus) | |
the end of the |
| ||
connector | Cable from | ||
backbone (bus) | |||
|
| sensor or | |
Cap for unused |
| display unit | |
|
| ||
connector |
|
|
NMEA 2000 network node located at the end of a NMEA 2000 backbone.
NOTE:
If you have a double T Connector on your network that is not at- tached to a device, you must cap the unused connector with a NMEA 2000 cap. This will protect the pin connectors from corro- sion. The NMEA 2000 cap looks like a terminator, but has "Cap" stamped into the connector housing.
6
