6
‘STORM’ R
ADIO
M
ODEM
RS232 / USB
Operational notes
RF data packets received by the Storm Modem with an embedded destination address which matches the
Storm Modem address will be accepted, processed and passed to the host, all other RF data packets will be
ignored.
The size of RF data packets is set during configuration. If fewer bytes are received by the Storm Modem than
the preset size, then after 10ms from the last byte received from the host, the RF packet will be processed and
transmitted anyway, (the data is expanded to meet the preset packet size).
The RF data packet size must be set the same for transmitter and receiver; otherwise the received packets will
be discarded.
In order to optimise data rate, in a point-to-point configuration where data is mostly being sent in one direction,
the packet size for one data direction can be set to the maximum size, however the reverse direction may be
set to a smaller packet size, to implement an acknowledge reply for example.
The Storm Modem contains an on-board data buffer equal to two data packets. Therefore if RTS is asserted
(then the host is unable to receive data) the Storm Modem will store a max of two data packets (2 x 31 bytes),
all further data packets received will be discarded.
Each Storm Modem has its own preset address. This is set during configuration. Any data received is
examined and the address header embedded within the data packet is compared with the Storm Modem
address. Only data received with matching address will be processed and output to the host, all other data will
be discarded.
DS Storm-b May 08
©2008 Reg. No. 227 4001, ENGLAND
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