3.1 Transmitting data
The AL205R is a fully-functional ALERT2 transmitter. When configured with the GPS as its clock
source and the GPS signal is strong, the AL205R/AL205B uses the assigned time-division multiple
access (TDMA) slot for transmission.
The AL205R can transmit ALERT2 data using the ALERT2 IND API over a serial port or using
A2Control on the Transmit Data window. Additionally, the AL205R sends status messages at user-
configurable intervals and upon acquisition and loss of the GPS clock sync.
3.2 Receiving data
The AL205R/AL205B receives and decodes ALERT2 data when powered. When the
AL205R/AL205B finds a valid Bit Sync pattern in the incoming audio, it turns on the Bit Sync LED
and begins listening for a valid Frame Sync pattern (which should immediately follow the Bit
Sync). If a valid Frame Sync pattern is found, the Frame Sync LED is turned and both LEDs will
remain lit for the duration of the incoming message. If a valid frame sync is not found, the Bit
Sync LED is turned off.
The AL205R/AL205B is a full-duplex modem. It decodes ALERT2 messages while the transmitter is
active and the radio has a full-duplex radio configuration. To view incoming messages, connect
to the device using A2Control, then select
. Messages are displayed as they are received.
AL205R / AL205B ALERT2 Repeater / Base
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