User's Manual

Page 36 FRH-SD07TU/TB Manual
3.4.3 Freque nc y Group Ope rat ion
The FRH-SD07TU/TB can operate on a fixed frequency or on any frequency in a set of
frequency group.
Multiple FRH (series) systems can be use different frequency groups and operate in the
same area without mutual interference between the systems. When the RF environment is
relatively clean, wireless channel links can be made on a fixed, clear frequency (no
interference) by using Grouping Method H. In less than ideal RF environments, it is better
to use multiple frequencies method in the frequency group (Grouping Method A through
G, multi-Access function). Since the modem searches clear frequency in the group, it
overcomes multipath fading and interference problems and establishes wireless
communications.
On the down side, wireless link establishment delays will become longer when using the
frequency group function (multi-access function) because the additional time is required
for searching the channels in the group with transmitting and receiving the packet on the both
end of the modem. The average connection delay will increase and the number of systems
that can operate independently in the same area will decrease as the number of frequencies
per group increases. Select the best grouping method for your application.
3.4.4 Grouping Me thods
The frequency grouping method and group number are set using memory register
REG06.
The following eight frequency grouping methods are available:
Method
Number of
Groups
Group Numbers
Frequencies
per Group
A 1 0 24
B 2 0 to 1 12
C 3 0 to 2 8
D 4 0 to 3 6
E 6 0 to 5 4
F 8 0 to 7 3
G 12 0 to 11 2
H 24 0 to 23 1
Table 3–7: Frequency Grouping Methods and Group Numbers
• In Grouping Method A, multi-access function uses all 24 frequencies.
• Frequencies are fixed in Grouping Method H, because only one frequency is available
in each group.
Rev. 050415-01.1