The MT-AIO has only one, three position control.
Selector Switch
The selector switch, located near the center of the PC board, is a three
position switch. In the center position, the MT-AIO is off. Even when left
off, the batteries should be removed for extended storage to prevent leakage
and damage to the device.
The other two positions are for selecting one of the two configurations
stored in the TT3 chip’s memory. The two pages of configuration selection
allow you to enter different frequencies, icons, transmission rates, FCC call
signs, tactical call signs, beacons, and all other programmable features.
The MT-AIO will ordinarily be shipped programmed with the
customers requested parameters, allowing instant on-the-air operations;
just add batteries.
On moving the switch to the channel 1 or channel 2 positions, the device
will send a transmission. This data will not include valid GPS data, since the
GPS will not have had time to synchronize. Subsequent transmissions will
wait for the GPS to acquire lock, and this may cause transmissions to be sent
at intervals different than those programmed into the device. For instance, if
you select 2 minute transmission intervals (the default option) and enter a
cave, the GPS will not synch up, preventing a transmission. Immediately
upon the transmission timing cycle requesting a transmission, the device will
verify that the GPS data is valid and hold off transmitting until verified. This
allows a tremendous power savings. A transmission can be forced by
returning the selector switch to center and switching to channel 1 or channel
2, as desired. Note that the device takes a few seconds to complete a
transmission on reset. When the unit is powered off and on, the TT3 PIC re-
flashes the stored frequency parameters into the transmitter. This memory is
non-volatile, and data will be retained even if the unit loses power for long
periods.