Selection of network Topology
In a
free topology network
, there are no demands as to how the cables are routed
between the nodes. It can be point-to-point, bus, star, tree, or a mixture.
Free Topology
Termination
When using free topology, the maximum cable length in one segment is approx. 500 meters,
and is calculated adding together all cables used. The maximum number of nodes in one
segment is 64. If more that 500 meters, or more than 64 nodes, is required, two or more
network segments can be made, using a repeater between each segment.
Bus Topology
In a bus topology network, all nodes are connected on a bus. Cable stubs can be used to
connect the individual nodes to the bus, as long as the length of the stub is maximum 3
meters. The advantage of bus topology, is that the cable length can be longer than when
using free topology. This can be useful e.g. when making network connection to remote PTZ
cameras.
Bus Topology
Termination
Termination
The maximum number of nodes on one bus is 64. Maximum length of the network bus
depends on the type of cable used. If more nodes, and/or longer cable length, is required,
two or more network segments can be made, using a repeater between each segment.
Termination
Each network segment require termination for proper data transmission performance. The
type of termination varies depending on whether Free topology or Bus topology is used.
In a free topology network segment, only one termination is required and may be placed
anywhere on the network. The termination resistor should be a 52
Ω
, 1/4W type.
In a bus topology network segment, two terminations are required, one at each end of the
bus. The termination resistors should each be a 105
Ω
, 1/4W type.
Termination resistors, which are included with the SYSTEM X keyboard, are easily fitted using
the LON
®
connectors on the SYSTEM X units as shown below.
S Y S E M
Page 4
2852-00001
LON
®
cable
Termination
resistor
