Topcon SRL-35 - Connection between Two Points; System of One Base Station and Several Substations

Repeater Mode and Addressing
Addressing
41
SRL-35 Operator’s Manual P/N: 1003224-01
Connection Between Two Points
When forming a connection between two points it is recommended that both the reception and
transmission addresses are identical in both radio modems. This is the easiest way to control addresses and
the risk caused by interference from other systems operating in the same area is minimal.
Example: by setting all addresses of both radio modems to a value ´1234´, they will accept only those
messages which contain this address, and they will use this same value when transmitting data.
If the channel is reserved for use only by the said network, or if the terminal devices are responsible for
addressing, it is not necessary to use addressing in the radio modems.
System of One Base Station and Several Substations
In systems with several substations, the base station must know to which substation each message is
intended, and from which substation each received message originates. Usually terminal devices handle
addressing completely, but it is also possible to use the addressing functionality of the radio modems.
For example, if the substation terminal devices are not able to check and form addresses by themselves,
addressing may be achieved with the help of the addresses of the radio modems attached to these terminal
devices. The base station may, in such a case, define the destination of a message by adding the address of
the corresponding radio modem into the beginning of the data packet. The substation radio modem(s) will
check the address and the corresponding radio modem will identify and remove the address characters. In
a similar way, the substation will add when transmitting to the base station its address characters into the
Reception addressing has
been set OFF.
The radio modem will
transfer all received data
to the RS-232 interface.
Reception addressing has
been set OFF.
The radio modem will
consider the characters of the
address as a part of the data
and will send all the
characters to the RS-232
interface.
Reception addressing has
been set ON but there is no
address in the data packet.
Data will appear on the RS-232
interface ONLY if the first 2
characters of the data match
either of its own RX address.
The radio modem will remove
those 2 characters of data.
Address
Address
ERROR