User's Manual

Company Confidential 22 Raveon Technologies Corp.
6. Connect your serial data device to the TXD and RXD pins of the I/O
connector. To connect the M8S to an RS232 serial port, you will need an
external digital to serial level converter.
The M8S is now ready to use. Any serial data going into the modem will be
transmitted over the air, and any data received over the air will be sent out the
serial port.
Remember, that from the factory, all M8S modems are configured to simply work.
Plug in power and connect to the serial port at 9600 baud, and the modems will
communicate on the default channel. Change the channel frequency to your
specific frequency, and they will be ready to work on your channel.
7.2. Programming Channels and Frequencies
The M8S modem has memory for up to 6 channels. A channel is a pair of
frequencies, one for transmit and one for receive. They may be different or they
may be the same. You may program any valid frequency into any channel
number. To program a channel, perform the following steps.
1. Change to the channel you wish to program, using the ATHP x command,
where x is the channel number.
2. Program the frequency for this channel x, using the ATFT, ATFR, or ATFX
command. Note that the frequency my be entered in MHz as long as you
use a decimal point. For Example, enter ATFX 450.1 to set the channel
frequency to 450.100MHz. Alternately, you may enter the frequency in hertz
by entering ATFX 450100000. You must enter all of the zeros if you enter the
frequency in hertz.
3. Review the frequency setting with the ATFT, ATFR, or ATFX command. To
see a list of all of the channels , enter ATF.
4. To change the radio channel, use the ATHP x command while the modem is
in the command mode.
7.3. 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, or when there is a pause in the data, the modem will automatically
key its transmitter, and send the data over the air.
Serial Port Baud Rate
While the modem is transmitting, the user may continue to send more data into
the M8. Because the buffers in the M8S are full-duplex, the serial port data rate
and the over-the-air data rates are independent. The serial port baud-rates may
be set slow to accommodate legacy equipment, or set at high-speed to minimize
latency. The over-the-air data rate us usually 4800 baud for narrow-band
channels, and 9600 baud for wide-band, although faster or slower rates may be
used.