Chapter Three
Operation
Man_805U Rev 1.8
Page
21
transmitted message will now have the second group address. Only 805U modules
configured with the second group address will accept the re-transmitted message.
If a transparent mode repeater receives a message on its second group address, it will re-
transmit the message on its first group address, but it will
not
output the data on its serial
port.
Here is an example :
Module A, B and C are
configured as transparent
repeaters. Module A is
configured with group
addresses 1 & 2, module
B with group addresses 2
& 3 and module C with
group addresses 3 & 4.
Module S and T are
configured with group
address 1 (only one group
address as it is not configured as a repeater). When S transmits a message, T and A will
receive it and output the data. If module X can hear the message, it will not output it as
module X is configured with group address 2.
Repeater A will re-transmit the radio message, but on group address 2. Module S and T will
receive the re-transmitted message, but will not output the message as the group address is
now wrong. Module X will receive the message and will output the message as the group
address is now correct.
Repeater B will also receive the re-transmitted message from A, and will output the data as
well as re-transmit on group address 3. The only other module which is also on group
address 3 is repeater C. It will accept the message and re-transmit it on group address 4 - to
module Z. Note that when a message is transmitted from a remote module, the repeaters will
only transmit a message in one direction. For example :
When X
transmits a
message,
repeater A will
receive the
message on
group address
2. Repeater A
will not output
the data as the
group address
is not the
repeater’s first
group address.
Repeater A will re-transmit on group address 1 to modules S and T. But repeater B will not
accept the re-transmitted message on group address 1.
A
B
C
G ro u p A d d re s s
F irs t
1
2
3
S e c o n d
2
3
4
S
T
X
Z
R e p e a te rs
R e m o te
M o d u le s
G ro u p A d d re s s
1
2
4
A
B
C
G ro u p A d d re s s
F irs t
1
2
3
S e c o n d
2
3
4
S
T
X
Z
R e p e a te rs
R e m o te
M o d u le s
G ro u p A d d re s s
1
2
4
