Radio techniques
Radio
Radio Bridge
ProGate can be a bridge for radio grouping. PTT system can group radios in each frequency. Below is steps of grouping process.

Locking steps : 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7
1) PTT is locked by radio device's PTT button.
2) Other devices are locked by radio frequency.
3) ProGate is locked by line(ProGate cable) of a radio device.
4) Channel manager lock on a channel.
5) ProGate is locked by a command of PTT server.
6) A radio device is locked by line(ProGate cable) of ProGate.
7) Other devices are locked by radio frequency.
Multi-locking of PTT
What happens Engaging the Lock on multiple radio devices at the same time?

As shown in figure, C can hear both of A and B. Sometimes it is useful for smart phone PTT system.
TDMA(Time Division Multiple Access)
Radio can use several channels in a frequency by TDMA.
