CL4490 User Guide
Version 3.0
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
20
Laird Technologies
The following rules apply to Sync-to-Channel:
1.
One server should perform the function of Hop Master.
2.
The Hop Master server should have its RF Channel Number set to a numerically low value and
should have Sync to Channel disabled.
3.
It is preferable to centrally locate the Hop Master server.
4.
All Servers in the collocated system (those synchronized to the Hop Master server) should have
Sync to Channel enabled.
5.
All servers in the collocated system should have their Sync Channel set to a value lower than their
RF Channel Number.
6.
All servers, including the Hop Master server, should have their RF Channel Numbers separated by a
minimum of 4-5 Channels (i.e. Server 1, Hop Master = RF Ch 16, Server 2 = RF Ch 21, Server 3 =
RF Ch 26…) to avoid inter-channel interference between the radios as they hop through their
pseudo-random hopping sequence.
7.
If the servers to be synchronized are in range of the Hop Master server, it is preferable to set their
Sync Channel to the RF Channel Number of the Hop Master server.
8.
If some of the servers to be synchronized are outside of the range of the Hop Master server, set
their Sync Channel to the RF Channel Number of a server (with a lower RF Channel Number than
its own) that is in range of, and synchronized to, the Hop Master server.
Note: All servers with Sync-to-Channel enabled depend on the server designated as Hop Master. If the
Hop Master is not powered on and in range, the Sync-to-Channel servers will not synchronize,
their LINK LED will not illuminate, and their networks will not communicate.
All collocated servers must be programmed to the same channel set, as shown in
Table 3: RF Channels for CL4490
Channel Set
RF Channel Number
Range (0x40)
Frequency Details & Regulatory
Requirements
Countries
0 (CL4490 - 1x1
CL4490 - 200)
0x00 - 0x0F
902 - 915 MHz (26 hop bins)
US / Canada
1 (CL4490 - 1x1
CL4490 - 200
CL4490 - 1000)
0x10 - 0x2F
902 - 928 MHz (50 hop bins)
US / Canada
2 (CL4490 - 1x1
CL4490 - 200
CL4490 - 1000)
0x30 - 0x37
915 - 928 MHz (22 hop bins)
Australia (-1x1/-200/-1000)
What happens if you don’t enable Sync to Channel and you have collocated servers? There are good odds
that you will see a decrease in throughput due to the systems trying to occupy the same frequency at the
same time. In severe cases, you could lose communications all together depending on how much bandwidth
your system requires. Due to crystal differences between the servers, you may see intermittent interference.
Sync to Channel is pictured in
