DB 15 PIN descriptions with input/output level
D-Type
Pin No.
Function
Description
Signal Type
Input/
Output
1
Data modulation IN
(Tx Mod)
Signal is directly injected to MOD through data
low pass filter without pre-emphasis.
Analog signal
1KHz audio at 60%
peak system deviation
input level =
100 to 120mVrms
I/P
2
Data unfiltered OUT
(RX disc)
Discriminator audio from the SD-170E. This is
the unprocessed AF signal prior to tone
filtering and de-emphasis.
Analog signal
1KHz audio at 60%
peak system deviation
produces
200 to 300mVrms
O/P
3
PTT In
(Tx Key)
Signal from the
„
external device
‟
to key the
SD-170 transmitter.
This line has an internal pull up resistor to +5V.
Pulling the line to 0V turns on the transmitter.
Note : If you installed option modem board,
you can select RS-232 signal level by
Jumper (CON407,
) on the digital board.
TTL level
0V = Tx
o/c = Rx
RS-232 level (option)
+12V = Tx
-12V = Rx
I/P
4
Power
B+ power connection.
DC +12V nominal
5
Serial Data Out
(TXD)
Serial data output for radio control or program.
It uses asynchronous data format.
TTL level
O/P
6
Busy
(CD)
Logic level output from SD-170 to indicate
whether a carrier is present or not
Note : If you installed an option modem
board, you can select RS-232 signal level
by Jumper (CON407,
) on the digital
board.
TTL level
0V = carrier
5V = no carrier
RS-232 level (option)
+12V = carrier
-12V = no carrier
O/P
7
Microphone filtered
audio IN
This signal is injected to the MOD at the point
through audio-amplification, pre-emphasis and
high pass filtering where sub-audio tone is
mixed with audio.
Audio
1KHz audio at 60%
peak system deviation
input level =
6 to 8Vrms
I/P
8
Serial data IN
(RXD)
Serial command or data input for radio control
or program. It uses asynchronous data format.
TTL level
I/P
9
Speaker filtered OUT
Audio output from the audio amplifier.
It
‟
s filtered by tone-filter, de-emphasis circuit.
Audio
1KHz audio at 60%
peak system deviation
produces
Nominal
1Vrms
@
8
Ω
O/P
10
Serial data IN for
option modem
The Serial data to be transmitted is input to
this pin. It
‟
s only available when option modem
board is installed. Inputted data are modulated
by modem IC and then injected to MOD.
It uses asynchronous data format.
RS-232 level
I/P
11
Serial data Out for
option modem
The recovered asynchronous serial data
output from the receiver. It
‟
s only available
when option modem board is installed. It uses
asynchronous data format.
RS-232 level
O/P
12
Serial data busy for
option modem
(reserved)
To eliminate data loss according to buffer
overrun of slave MCU
‟
s memory, it indicates
buffer status.
RS-232 level
O/P
16
