SATEL-EASy+
User Manual
Version 1.19
56
13.3.1
System with several repeaters
In systems with several serial or parallel-chained repeaters, addressing must be used to prevent
messages from ending up in loops otherwise formed by repeaters, and to ensure that only the
desired (addressed) radio modem receives the data intended for it.
All radio modems in the network must be set to a state, in which the RX-addressing is switched
ON and TX-addressing is switched OFF. Base-station and all substations add an address string in
the beginning of the data to be transmitted. In the relaying of the message addressing is used in
the following way:
R1 ADD R2 ADD S ADD
DATA
- The above is the data received from the base station terminal device, containing repeater
addresses (R1 ADD, R2 ADD) and the substation address (S ADD). Two characters define each
address.
R2 ADD S ADD
DATA
- The above is the same message after being relayed from repeater 1 to repeater 2.
S ADD
DATA
- The above is the same message after being relayed from the last repeater in the chain
(repeater 2) to the substation.
DATA
- The above is the same message being relayed via the serial interface of the substation radio
modem to the terminal device.
In a situation where the substation transmits data towards the base-station the address is
formed in a similar way, but the order of the addresses is reversed:
R2 ADD R1 ADD M ADD
DATA
-In the above, R2 ADD is address of repeater 2, R1 ADD is address of repeater 1 and M ADD is the
address of the base-station.