M7 GX Technical Manual
46
Raveon Technologies Corp.
10. Technical Information
10.1.
Device Addressing
Addressing Basics
One of the more powerful aspects of the
RV-M7 GX
transponder is its addressing
scheme. Addressing allows multiple radio systems on the same frequency to co-
exist, and not interfere with each other. Addressing is used to differentiate one
RV-M7 Transponder from another. Each unit has a unique number, so that when a
position report is received, the
RV-M7 GX
that sent the message is known. It is not
a security measure. Use the Security KEY to protect messages from being
intercepted. Use the Addressing to identify individual
RV-M7 GX
transponders.
Firmware version B9 and higher includes a “Group Number” feature. If the group
number is set to 0, this feature is ignored. If the Group Number is set to a number
between 1-254, then the Group Number feature is automatically enabled, and all
other radios in the system that wish to communicate with each other must have the
same group number. If the group number of two modems do not match, they
cannot communicate. The Group Number is set with the
ATGP xxx
command.
Each
RV-M7 GX
has a Unit Address programmed into it, and is represented as a 4
digit number.
RV-M7 Unit Address
address may be any number between 0001
and 9999. Every
RV-M7
has a Unit Address programmed into it, as well as the ID
of the unit it will send data to. The Unit Address is programmed with the
ATMY
xxxx
command, and the Unit Address of the destination modem (the Destination
Address) is configured with the
ATDT xxxx
command.
Note: The underlying digital technology is a 16-bit address, and thus the valid
address range is 0000
– FFFF in hex. Because the
RV-M7 GX
TDMA channel
access method uses the decimal version of the ID to determine slot number, digits
0-9 are valid, but A-F should not be used.
This addressing scheme allows up to 9999
RV-M7 GX
transponders to be on one
radio channel, or split-up into sub-groups so they do not interfere with each other
1
.
For example, one group could use IDs 1200-1299 and another group use IDs
1300-
1399. When properly configured, the two groups will not receive each other’s
signals.
The default Unit Address in all
RV-M7 GX
modems is 0001, and 0001 is the default
for the destination ID also. An Address Mask is used to select which digits of the
address will be used to determine if a particular reception was intended for the RV-
M7 modem. The default Address Mask is F000, which means the
RV-M7 GX
will
receive a transmission from any other RV-M7 as long as the fist digit matches, in
this case, is a 0.
1
Tech Note: The addresses are actually 0000-FFFF hex, allowing 64K addresses, but the TDMA
transmission used in the M7 GX interprets them as decimal numbers, and ignores HEX characters.
