User Manual

Operation
RFI-9256 Radio Modem User Manual Page 23 of 96
edge detected on the synchronisation TTL input. This mode should be used when a master is
following a collocated slave, such as when they are in back-to-back repeater configuration.
Synchronisation does not operate correctly when directional bias has been enabled on either unit.
MASTER / SLAVE CONFIGURATION
A network of RFI-9256 radio radios will consist of one master, and one or more slaves. Multiple co-located
masters are supported in the RFI-9256 system through three mechanisms:
 Hopping Pattern. Each master unit has a unique hopping pattern. The hopping pattern determines
the order that the master hops over all available channels. There are 32 available hopping patterns,
and these have been selected so as to cause minimum interference between co-located masters.
 Network Address. The network address is a number between 0 and 63 that defines the network to
which the master belongs. The network address provides a second layer of differentiation between
multiple masters.
 Security Code. Each RFI-9256 can be programmed with a 32-bit security code. A slave will only
be able to communicate with a master if both units have the same security code.
The master and all the slaves in a single network must be configured with the same values for hopping
pattern, network address, and security code.
BACK-TO-BACK REPEATER OPERATION
The RFI-9256 supports network extension through the use of a back-to-back repeater. A back-to-back
repeater consists of two RFI-9256 radio radios. This is shown in Figure 7.
RFI
-
9256
Master 1
HPSN=0
Addr=1000
RFI
-
9256
Slave 1
HPSN=0
Addr=20
RFI
-
9256
Master 2
HPSN=1
Addr=20
RFI
-
9256
Slave 2
HPSN=1
Addr=3000
Wiring
Harness
Figure 7: Back-to-back repeater configuration
A back-to-back repeater configuration is the joining two separate RFI-9256 networks via a wiring harness
between a slave on one network and the master of a second network. The wiring harness can link the main
port, auxiliary port, or both ports via a null-modem cable. A wiring diagram for a back-to-back repeater
cable that links both main, auxiliary, and the auxiliary I/O lines is given in Appendix A.4.
When setting up back-to-back repeaters, the following rules should be followed: