SATELLINE-2ASxE
User Guide, Version 2.0
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5.2 A connection between two points
In connecting two points it is advisable to set both the receiving and the transmitting addresses
equal in both radio modems. This is the easiest way to control the addresses and the risk of
interference from other systems working in the same area is minimal.
It’s not necessary to use addressing if a special radio channel is reserved for use in the area or if the
terminal takes care of addressing.
5.3 A system with one base station and several substations
In a system with several substations it is necessary for the base station to know to which of the
substations the message has to be sent and from which substation the message is received. When
planning the system there are at least two different possibilities to make use of the addresses in the
radio modem. It is also possible that the terminals take care of addressing and in this case the
feature of the radio modem is not needed.
The address of the base station can always be changed when transmitting from one substation to
another. In this case the base station can only listen to one substation at a time. In a polling system
it is possible to use this arrangement because the radio modems communicate with each other in
pairs.
In a system with Carrier Sense Multiple Access (CSMA) it is not possible to use addressing at the
base station as it would prevent the base station from hearing all the substations. It is useful to
change the address of the base station according to the substation in a polling system. It is the
terminal of the base station that should take care of the addition of addresses and checking of data
packets.
In these applications the radio modem at the base station is left without an address and the radio
modems at the substations are set with both the transmitting and the receiving address. The
software of the base station must be able to treat the addresses given by the base station and to
add the addresses of the substations to the data packet.