16
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
