Technical Details; Installation Planning - NorthStar 972 Installation Manual

SECTION FOUR: Networking the Northstar 972
• if an NMEA device is connected to a slave unit, that slave must be turned on and operating
for that device to be functional across the network
• should there be a failure in the master unit, a slave could be temporarily moved to that
location, and this is easier to accomplish if all interfaces connect to that same unit
However, NMEA devices can be connected to any networked unit, if necessary.
Restrictions on networking
There are only four restrictions on the use of networking. These restrictions must be observed, or the
network will not function.
• one and only one master must be a part of any network
• the master unit must be turned on at all times when the system is in use
• all units on the network must have the same software revision
• at present, a maximum of five units may be connected on any network
If the master unit becomes unavailable for any reason, the user is prompted with instructions to
temporarily designate a slave unit as a master.

Technical details

The networking port found on the Northstar 972 devices conforms to the electrical specifications set
forth by the IEEE 802.3u 100Base-TX standard. This standard is also referred to as "Fast Ethernet. "
The cabling used is data grade category 5 or 5e Unshielded Twisted Pair (UTP) terminated with RJ-45
connectors on both ends. The standard allows for transmission of raw data at speeds of 10 and 100
Megabits per second depending on the device being communicated with. Although Fast Ethernet is a
commonly used standard, particularly in computer Local Area Networks and peripherals, the 972
should only be connected to equipment specified by Northstar to avoid unexpected operation.

Installation Planning

Ethernet cables should be kept several inches away from power cables and other wiring that might
generate interference (such as radar and echosounder cables). When necessary, Ethernet cables
should cross these other cables at right angles.
Standard off-the-shelf Ethernet cables can be used. These cables are available in a variety of lengths
and can be obtained from sources that carry computer networking supplies. The installer should
ensure that the cable is category 5 or category 5e cable. Other cables, particularly voice grade cables,
look very similar but will not work properly.
Page 18 972 Installation Manual, Rev. B