7
Explanation for internal processes (1) (automatic channel search)
The automatic channel search is a system that detects the carrier level of the channel in use to search for vacant
channels in order to avoid interference with other radios. This is controlled automatically by the built-in micro-
computer.
The channel search is executed by the module from the pre-determined starting channel.
For example, if the channel search was executed from [0ch], the procedure would be as follows:
(1) The STD-402 is set in the receiving mode
(2) Set at channel 0 (433.200MHz)
(3) The carrier level is detected and compared with the standard level
(4) If the channel is occupied, the frequency is increased by two channels (50kHz.)
(5) If the channel is vacant, the system is switched across to the transmission mode
(6) The vacant channel is set
(7) Transmission is started
Set 0channel
Set receive mode
Sense carrier level
Occupied channel?
Increment 2ch(50kHz)
Channel Search
Yes
No
Set channel
TX starts
To automatic link
Set tarnsmit mode
0ch
433.200MHz
1
2
5
3
4
6
7
8
63ch
434.775MHz
62
50kHz
Channel incerement in order 0,2,4,,,,,,,,,,62,1,3,5,,,,,,63
* Cannot verify the set channel from an external
source.
* Refer to the direct mode manual for a list of
channels and frequencies.
