MDS 05-3438A01, Rev. F
MDS 4790/9790 Series I/O Guide
23
Data Interface Connector—J3
The data connector on the radio’s rear panel is the main system data
interface. It typically connects to the host computer. Refer to
Figure 21
and
Table 5 on Page 23
for pinout details. Refer to
Figure 22 on Page 24
for information on connecting the radio to a VOX assembly.
Invisible place holder
Figure 21. Data Interface Connector, J3
Table 5. Data Interface Pinout
Pin
Number
Input/Output
Pin Description
1
—
Shield Connection.
Connects to ground (negative
supply potential) on the radio’s PC board.
2
IN
TXD—Transmitted Data.
Accepts TX data from the
connected device.
3
OUT
RXD—Received Data.
Sends received data to the
connected device.
4
IN
RTS—Request-to-Send Input.
Keys the
transmitter when RTS is asserted.
5
OUT
CTS—Clear-to-Send Output.
Active after the
programmed CTS delay time has elapsed.
6
OUT
DSR—Data Set Ready.
Provides a +6 Vdc DSR
signal through a 2.5 k
Ω
resistor.
7
--
Signal Ground.
Connects to ground (negative
supply potential) at the radio’s PC board.
8
OUT
DCD—Data Carrier Detect.
Activates when the
radio detects an on-frequency signal.
9
--
No Connection
10
--
No Connection
11
OUT
Receive Audio Monitoring Connection
(used for
diagnostics). Drives high-impedance load.
12
--
No Connection
13
--
No Connection
14
--
No Connection
15
OUT
Do not connect—Reserved for future use.
16
--
No Connection
17
--
Do not connect—Reserved for future use.
1
13
25
14
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