Service manual

User Manual SD125E
Page 10
English
SD125E Series Operation
16 Channel select
Your radio’s channel can be selected by inner DIP-S/W or serial command inputted from external
control system. To change channel by inner DIP-S/W (4), you should open the upper cover and
then look for the DIP-S/W (4) on the digital board of the bottom cover. Once located change the
DIP-S/W to select wanted channel according to channel dip switch chart (See page 11).
To use a serial command for channel selection, it should be inputted by external equipment or
device (ex. Personal computer). See the message format for serial command for full details.
Transmit
The transmission will be made by various inputs such as PTT signal (Pin 3 of DB-15 connector),
TTL level is used as PTT signal and is active low. To maintain transmission, continuous PTT signal
input is required. When the channel is “clear”, input the PTT signal and transmit data. Remove
the PTT signal or input Rx serial command when you have finished transmission.
CAUTION: Operation of the transmitter without a proper antenna installed may result in
permanent damage to the radio.
Receive
When you have finished transmission, remove the PTT signal. You will be in the RX mode and can
receive data from another radio.
Pin-outs DB-09 Connector
DB9 CON 401
Pin1 Audio In (Data RX) 2
Pin2 Audio Out (Data TX) 5
Pin3 PTT 8
Pin4 GND (Ground) 11
Pin5 B+ (8-18 Volts DC) 14
Pin6 Carrier Detect (Squelch) 1
Pin7 N/C No Connect 4
Pin8 Switch 7
Pin9 N/C No Connect 10