No
. 96-1886-01E
Rev
.
1.1
GTECH Aircon Radio (Model GWT154)
PAGE
25
OF
72
5.0
WIRELESS DATA TRANSPORT
5.1
End
Device
selection
The destination address of the currently selected End Device radio is interpreted by the Coordinator
from the GTECH485 SYN address packet. When the Coordinator intercepts the GTECH485 SYN
protocol character it is to broadcast that packet to all radios in the PAN, to place any currently
connected Peripherals in the OFF-line state. The Coordinator radio will inhibit any further
communication with End Device radios by setting its connected radio address to NULL. The End
Device radio’s Peripheral addressed by the broadcast SYN address packet will reply with the
appropriate response packet. The Coordinator radio upon receiving a SYN response packet from an
End Device radio will save that radio’s address as the new connected End Device radio address. The
response packet from the addressed Peripheral is relayed back to the Host CPU.
The End Device radio remains selected until another SYN protocol character is detected. All
GTECH485 data packets seen by the Coordinator are relayed to the selected End Device radio and to
the Peripherals on its local 485 bus.
In the event the Coordinator is selected by the SYN address packet as the Peripheral, the Coordinator
will broadcast the SYN Unlisten address to set all peripherals OFF-line.
