M7 GX Quick Start Guide
16
Raveon Technologies
ATMK F000 <enter>
7.5. Time Slots
For optimum efficiency in a
M7 GX
system, begin
sequentially numbering the MYID of the
M7 GX
transponders at ID 0001. The second M7 should be ID
0002, and so on.
The
M7 GX
transponders have internal clocks with 20 ticks-
per-second. They can measure time and initiate
transmissions 20 times every second (every 50mS). The
factory default allocation is each TDMA time slot is 200mS
long, and thus in 10 seconds, up to 49
M7 GX
transponders
may report position. These parameters are programmable,
and may be re-configured based upon the type of system
they are used in. Program the slot time with the
SLOTTIME
xxx command, where xxx is in milliseconds.
For over-the-air rates of 4800 baud, Raveon Suggests using
a
SLOTTIME
of 200mS when using a repeater, or 100mS if
there is no repeater in the system.
For over-the-air rates of 9600 baud, Raveon Suggests using
a
SLOTTIME
of 150mS when using a repeater, or 50mS if
there is no repeater in the system and no encryption used. If
no repeater is used, but encryption is enabled, then use
70mS for the SLOTTIME.
A TDMA “Frame” time is the time it takes all units in your
system to transmit. This is configured with the
TDMATIME
xx
command. The factory default is 10 seconds, so every
10 seconds, each
M7 GX
is allocated a time-slot that it may
use to transmit position in. The TDMA frame must be set
long enough for all units to transmit. For example, if you
have 199
M7
s, and use 200mS TDMA slots, then the
TDMATIME
should be set to 40 seconds.
All TDMA frames are synchronized automatically in all
M7
GX Transponders
to the top of the minute. Slot 0, frame 0
is at the top of each minute. Slot number 0 is used for future
protocol options, and should not be assigned to any unit.
8. Installation
1.
Secure the
M7
modem using the mounting holes on
the side flanges of the unit.
