Specifications

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8. INTERFACING
8.1. External connections
Connection is made to the SD-160 via an external 50 ohm BNC socket (RF signal) and a high
density 15-way “D”-type socket (DB-15 connector; control and data signals) with 4-40 UNC
threaded jack posts for more permanent connection. Besides, SCN-12 type circular connector is
added to separate power line from data and analog signals of DB-15 connector.
8.2. 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-160. 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-160 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.
See Figure 8.2.
TTL level
0V = Tx
o/c = Rx
RS-232 level (option)
+12V = Tx
-12V = Rx
I/P
4 Ground Ground connection to chassis of the radio. 0V (Chassis)
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-160 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.
See Figure 8.2.
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