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CL4490 User Guide
Version 3.0
T
O
HEORY OF
PERATION
RF Architecture
The CL4490 utilizes a server-client network where all clients synchronize their hopping to the server. The
server transmits a beacon during the first 1 ms of every hop (20 ms). The client transceivers listen for this
beacon; upon hearing it, they synchronize their hopping with the server and the LINK LED illuminates.
Each network should consist of only one server. Two servers should never use the same RF Channel number
in the same coverage area – the cross-talk between the two servers severely hinders RF communications. For
those applications requiring collocated servers, Laird recommends using the Sync to Channel feature, further
explained in
Appendix II: Sync to Channel.
Network Topologies
Topology refers to the shape of a network, or the network's layout. The way different nodes in a network
connect to each other and how they communicate is determined by the network's topology. The CL4490s
support a Point-to-Point and a Point-to-Multipoint network topology.
Point-to-Point
A Point-to-Point system is a simple arrangement consisting of just two CL4490s programmed to the same
System ID and RF Channel (a single server/client pair). Sometimes referred to as a wireless bridge, a Point-to-
Point link replaces a single communications cable. You might use a Point-to-Point link to connect a
programmable logic controller (PLC) to a remote monitoring station.
Point-to-Multipoint
Point-to-Multipoint systems have one base station, or access point, that controls communications with all of
the other wireless nodes in the network. This allows you to create a wireless network with multiple nodes. By
programming each CL4490 with a network-specific Channel Number and System ID, multiple networks can
coexist. You may configure collocated systems by programming each system with a network specific System
ID and RF Channel Number. See
Figure 3
for an example of collocated point-to-multipoint systems.
Figure 3: Point-to-multipoint systems
7
Laird Technologies
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
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