Repea
ter Mode and Addre
ssi
ng
Using Repeaters and Addresses in the Same System
43
SRL-35 Operator’s Manual
P/N: 1003224-01
Repeater Chain Using Address Pairs
In a situation where the terminal devices and substations cannot form address fields, but are able to
recognize messages addressed to them, alternating address pairs may be used. Transmit address (TX) and
receive address (RX) alternate in the order shown in the table below.
In a network where alternating addresses are utilized, the exact route that is used to relay a message to a
certain radio modem is fixed at the time of installation and configuring the system. The order of the
addresses must be the same as the order of the route that is used to relay the message to the said radio
modem. It should be noted however, that in network where alternating addresses are used the base-
station and substations will hear their own messages repeated.
Repeater Chain using Dual Addressing
If the terminal devices cannot add address chains to the beginning of the data packets, a network with
several repeaters may still be realized by using dual addressing. In dual addressing each link (see arrows
below in figure) is given a unique address, which will prevent duplication of messages and endless loops in
the network. The terminal devices need not add anything to the data.
Usually the primary transmit address is used in transmission (TX1). The secondary transmit address (TX2)
is used only if the R
epeater Mode
is used and the packet to be repeated was received using the secondary
reception address (RX2).
In the following example two repeaters are used. It should be noted that each link (arrow) might be
uniquely defined with the help of radio modem numbers and data transfer directions. The
Repeater Mode
should be switched ON only in the radio modems acting as repeaters to prevent the packets from remaining
in endless loops in the network.
Repeaters may also act as ordinary substations; in that case the terminal device must wait until the
message has reached the end of the repeater chain before sending data.
Figure 13: Repeater Chain Using Dual Addressing
Table 18. Address Pairs
Address type
Base-station address
Repeater 1 and the addresses of
the substations of the base-station
Repeater 1 substations
addresses
TX address
Address 1
Address 2
Address 1
RX address
Address 2
Address 1
Address 2
