RV-M50-E Technical Manual
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4.4.
Data Transmission
To transmit data, send one or more bytes of data into the serial port of the modem. When a full packet
of data has been collected into the internal buffer of the modem; there is a pause in the data per ATR3;
or the maximum packet size is reached, the modem will automatically key its transmitter, and send the
data over the air.
4.5.
Data Reception
Serial Port Data
When the modem receives data over the air, it checks it for errors, and if it is error-free, it will send it
out the serial port. Again, the serial port may be set to any baud rate the user wishes, and the radio
receiver and transmitter will continue to operate independently of the baud rate.
4.6.
Device Addressing
ID Addressing Basics
ID addressing is used to differentiate one modem from another. Each must have a unique number
programmed into them, so that when a position report is received, the modem that sent the message
can be identified. This is called the MYID of the unit that sent the message.
Each modem has a MYID programmed into it, and is represented as a 4 digit hexadecimal number.
Addresses between 0001-FFFF are valid. The Unit Address is programmed with the
MYID xxxx
command, and the ID of the destination modem it sends its messages to (the Destination Address) is
configured with the
ATDT xxxx
command.
The factory default
MYID
in all modems is 1234, and 1234 is also the default for the Destination ID also.
The default Address Mask is F000, which means the modem will receive a transmission from any other
modem as long as the first digit of the destination address matches, in this case, is a 1.
Make sure you set the
MYID
of each modem in your system to a different number.
For example, to set the ID of your modem to 17, enter:
MYID 17 <enter>
To set your modem to send its position and status data to modem number 1, enter:
ATDT 1 <enter>
To set your address mask to receive all messages from units with IDs 1-999, and exclude 1000-9999,
enter
ATMK F000 <enter>
An alternate way to disable addressing altogether, is set the Address Mask to 0000 (ATMK 0000
command). This tells the radio to ignore the address, and receive every transmission.
