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Cooper Bussmann 945U-E Wireless Ethernet Modem & Device Server User Manual
21
Rev Version 2.14
Regions will only show the available channels for that location. Figure 18 shows the frequency ranges and channels.
Figure 18 900MHz Channels
Each country or region has a different frequency regulation with multiple band widths and numerous channels
available. The main reason for having different channels and bandwidths is to allow multiple radios to operate
in close proximity with minimal interference. As you can see from the Channels Diagram (above) and the Data
Throughput Table (in the following section), the greater the band width, the greater the overall data throughput.
If selecting the high band width, for example 20 MHz, you will be limited to one channel, which may be more
susceptible to outside interference because it spans the available 900-MHz frequency range. In some regions this
high band width option may not even be available. If selecting the lower bands, for example 1.25 MHz, you have
more channels available and each channel is non-overlapping (adjacent channels do not cross over). However, the
data throughput will be considerably lower. If you require high data throughput, the higher band width will need to
be selected and care will also need to be taken with antenna placement.
Selecting a 20-MHz channel will give the maximum TCP/IP throughput of around 22 Mbps, but if the band width is
reduced (for example, 10 MHz or 5 MHz) the maximum data throughput will also be reduced. For an indication of
the data throughput levels used with different channel bandwidths see the 945U-E Radio Data Throughput table in
the next section.
Radio Throughput
Below is a table showing the maximum TCP/IP throughput based on channel selection and receiver signal level.
There are five channel bandwidths (20, 10, 5, 2.5, and 1.25 MHz). These throughput estimations are based on
perfect radio conditions that assume little to no outside radio interference present while data is being passed, and
they are calculated using real-life conditions and communication constraints. Higher data rates are achievable by
using an external Iperf arrangement. For details, see “4.4 Throughput Test.”