SATELLINE-3AS and SATELLINE-3ASd
19
5.3
5.3
Data Transmission (Radio-interface)
Data Transmission (Radio-interface)
5.3.1
Addressing
It is possible to use addresses both in data transmission and reception on the radio channel. The
address consists of two data characters (totalling 16 bits). The address consists of the first two
characters of the data packet, that the radio modem adds to every sent packet and/or checks for
in every received packet. (compare to SL-command SLAxy, where ADD H corresponds to x and
ADD L corresponds to y)
Address range is from 0000h (h for hexadecimal) to FFFFh in hexadecimal format (0-65535 in
decimal format). The maximum data length is 1 kB (kiloByte) with a repeater, in normal use it is
not constrained.
ADD H
ADD L
DATA
For example, address 1234h (4660 decimal) where 12 is ADD H and 34 is ADD L.
For another example, ABFFh (44031 decimal) where AB is ADD H and FF is ADD L.
The addresses can either be the same in both directions or the transmitting and the receiving
addresses can be different. It is also possible to transfer the received address to the RS interface.
You can use addressing for
-
preventing unwanted messages for DTE’s that might not handle it (multi-slave system)
-
preventing messages circulating between repeaters
5.3.1.1
Transmission
Data
Address Data
Data
Data
Fig 1. Address of transmission has been
set OFF. Radio modem will transmit the
data packet as such.
Fig 2. Address of transmission has been
set ON. Radio modem will add the
address to the beginning of the data
packet.
