ARF868 Radio Modems - User guide version V1.8.1
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Addressed mode with sub-network:
The products always communicate within the same sub network. This means that two products with identical addresses and different sub-
network numbers do not communicate with each other. The only case of inter-network communication is when S256=255 and S253=255.
•
S220=1 (address mode)
•
S253= sub network number varying from 1 to 255 (255 is used for broadcast between the sub-network)
•
S252= local address (address on 8 bits)
•
S256= recipients address (address on 8 bits, 255 is the broadcast address within the sub-network)
3.3. Legacy X3-PRO protocol
The “legacy X3-PRO” protocol provides the ARF868 modem with total “air” compatibility with the previous generation Adeunis-RF X3-PRO
type modems.
Compatibility is provided for Narrowband and Wideband modes, and for Address and Transparent modes.
Please refer to the dedicated application note: ARF868 Radio Modems: «Legacy X3-PRO» mode, available on our website.
4. Advanced product functions
4.1. UART interface self-detection
The ARF868 modem has automatic interface detection at switching on enabling a selection of the RS232 or RS485 mode. Automatic detection
is activated when interface selection register S215 is positioned on the value 4.
For detection in the RS485 mode it is essential to have an earth connected to the product. Otherwise the detection motive ”U“ cannot be taken
into account.
4.2. Autobaud: Self-detection of the serial link data rate
On switching on with the SubD9 cable connected, the modem detects the data rate on the serial link of the monitoring equipment in order to
synchronise itself on its parameters.
For this detection to be performed, the equipment must send, before any command or character chain, the synchronisation command: “ U “
After a positive reply from the modem, it is then operational and switches to the communication mode. It will be capable of transferring the
characters seen on the serial link onto the Air link or entering the command mode (see § 5.2 command mode input/output).
Command
Description
Answer
U (upper case)
Allows automatic detection of UART data
rate (see
note 1
).
Returns the parameters of the serial link :
RS232 or RS485 and data rate.
Note
:
To this request the modem will reply by the configuration that it has detected: type of link, UART data rate. E.g.: RS232, 9600.
If the modem does not reply or replies by another character chain to the synchronisation request U, a new test can be attempted, after having
disconnected and reconnected the electricity supply to the appliance. If these attempts produced no effect, check that the serial link of the moni-
toring equipment is set to: 8bits, 1 stop bit, no parity and that the UART proposed corresponds with one of the data rates available in register
S210.
Sending of the synchronisation character “U” is only useful on first switching on or as long as a UART configuration has not been memorised on
registers S210 by the AT&W command.
On equipment that is already synchronised, it will not be interpreted as a synchronisation request and will be transferred onto the air link like
any other character chain.
The self-detection mode (type & data rate) will be retained for the next switching on in the following three situations:
•
No saving of register S210 by the AT&W command before switching off.
•
Brief pressure on BP1 before the power is cut off
•
Return of register S210 to the value of 0 by ATR and AT&W commands before the power is cut off.
