Company Confidential
25
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.
Streaming Mode Advantages
1. Low Latency:
The transmitter will key-up immediately upon the
user’s first byte of data entering the modem. Packetized
operation waits until a packet has been loaded before keying.
(Although high serial-port data rates can minimize this packet
latency to a negligible level). When receiving, data comes out the
serial port as it is received. In packet mode, data output starts at
the end of the packet once the CRC is verified and any
decryption is complete.
2. Data with Errors:
Packet mode does not output corrupted data.
But when a streaming mode radio is receiving data, it works
down into the noise-floor of the radio. If the channel is noisy or
the signal is weak, there will be bit-errors in the data. At the end
of a transmissions, the modem may output additional noise data.
User applications must (and often do), take this into account.
8.2. 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
.
