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MDS 4790M (MPT 1411) I/O Guide
MDS 05-3628A01, Rev. B
Table 3. Data Interface Pinouts
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.
Outputs received data to the
connected device.
4
IN
RTS—Request-to-Send Input.
Keys the transmitter
when RTS 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 V dc DSR
signal through a 2.5 k
Ω
resistor.
7
--
Signal Ground.
Connects to ground (negative supply
potential) at radio’s PC board.
8
OUT
DCD—Data Carrier Detect.
Goes active when the
radio detects an on-frequency signal.
9
IN
No Connection
10
OUT
No Connection
11
OUT
Receive Audio Monitoring Connection
(used for
diagnostics). Drives high-impedance load.
12
IN
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.
18
IN/OUT
No Connection
19
OUT
14.0 V dc Output.
Provides a source of regulated
voltage at 1.5 amperes for low-power accessories.
20
--
No Connection
21
OUT
No Connection
22
--
No Connection
23
IN
No Connection
24
--
Do not connect—Reserved for future use.
25
OUT
No Connection
