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Chapter 3. Basic Operation
3.1. General
The B900ss-20 can operate with three data communication modes:
•
"Hayes": inspired from the standard Hayes for voice modems, it is used to
program the modem's parameters.
•
"Point-to-Point": Two B900ss-20 replace a cable (the Half-duplex operation copies
the function of an RS-485 cable). This mode automatically handles the data security
(encapsulation, iterations, etc.)
•
"Network": Several B900ss-20 can work together, in accordance with a
Client/Server structure. A Server will then be able to handle up to 16 clients
simultaneously.
3.2. "Hayes" Mode
The Hayes commands used by the radio module are in conformity with the Hayes
protocol standard used for the voice modems. This protocol is based on the following
principle: A data frame always starts with the two ASCII characters "AT" for
"ATtention". The commands follow and are coded on one or several characters
eventually with additional data.
Since the B900ss-20 does not operate exactly like a voice modem, it includes additional
"AT" codes.
These commands are principally used to read and write the data in the configuration
registers stored in EEPROM.
