25
STD-402 RF-SYNTHESIZER
Description of the Functions
The frequency range of the STD-402 synthesizer
extends from 429.2500 MHz to 429.7375 Mhz. The
radio module works on one of the 40 different
frequencies. The frequencies can be individually
selected, or can be separated into four groups with 10
channels each. The individual frequency or groups are
selected via a 6-pin DIP switch array.
NOTE:
Operation of the RF Unit STD-402R is
approved by TELEC for use in Japan, and there are no
additional licensing requirements.
IMPORTANT:
Disconnect all power to the transmitter
and receiver before making any change to the
frequency.
Description of the Transmitter Module
The RF unit has a permanently affixed antenna and
receives input power and TTL data by the 3-pin Dubox
connector (see picture).
Description of the Receiver Module
Depending on the DIP switch array configuration, the
RF Unit continuously scans for valid frequency
channels, or scans for an individual frequency. In the
continuous scan mode, it locks onto a valid frequency
channel once it receives an input signal on the 2-pin
Dubox connector (see picture). The RF unit has two
SMB diversity antenna inputs. Input power, and TTL
signal output, is provided by the 3-pin Dubox connector
(see picture).
Scan Mode
Upon power up, the RF Unit scans for an open
frequency channel depending on the DIP switch array
configuration. Once an open frequency channel is
found, the RF unit locks onto that channel, and begins
transmitting data.
Individual Frequency Mode
Upon power up, the RF Unit checks to see if the
individually selected frequency channel is clear. If the
frequency channel is clear, the RF unit begins
transmitting data. If the frequency channel is not clear,
the RF unit will not transmit data.
ON
1
BLU
WHT/BLU
RED
2 3 4 5 6
TX
RX
1 2 3 4 5 6
ON
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