User's Manual
MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 59
Invisible place holder
Figure 29. Data Interface Connector (DB-25) Pins
(As viewed from outside the radio)
Unused
Radio Inhibit (Sleep)
Unused
13
12
11
10
9
8
7
6
5
4
3
2
1
Receiver Unsquelched Sensor
Unused
Data Carrier Detect (DCD)
Signal Ground*
Data Set Ready (DSR)
Clear-to-Send Output (CTS)
Request-to-Send Input (RTS)
Received Data (RXD)*
Transmitted Data (TXD)*
Protective Ground
25
24
23
22
21
20
19
18
17
16
15
14
Alarm Output
Analog Input Pin
Diagnostic Channel Enable
RSSI Voltage
9.9 Vdc Regulated Output
Unregulated DC Input/Output
Digital Output Pin
Unused
Unused
Unused
Pin
Description
Pin
No.
Pin
No.
Pin
Description
Unused
Future use— do not connect
* Required in most installations
Table 15. Data Interface Connector (DB-25) Pin Descriptions
Pin
Number
Input/
Output Pin Description
1--Protective Ground
Connects to ground (negative supply potential) on the
radio’s PC board and chassis.
2INTXD—Transmitted Data
Accepts TX data from the connected device.
3 OUT RXD—Received Data
Supplies received data to the connected device.
4INRTS—Request-to-Send Input
5 OUT CTS—Clear-to-Send Output
Goes “high” after the programmed CTS delay time has
elapsed (DCE), or keys an attached radio when RF data
arrives (CTS KEY).
6 OUT DSR—Data Set Ready
Provides a +6 Vdc DSR signal through a 2.5 kΩ resistor.
7--Signal Ground
Connects to ground (negative supply potential) at the
radio’s PC board.
8 OUT DCD—Data Carrier Detect
A “high” indicates hopping synchronization.
9 -- Unused.
10 OUT RUS—Receiver Unsquelched Sensor
Provides +8 Vdc through a 1 kΩ resistor whenever the
receiver squelch is open, and drops to less than 1 Vdc
when the squelch is closed.
11 -- Unused.
12 IN Sleep Mode
A ground on this pin turns off most circuits in the radio,
including transmit, receive, modem and diagnostic
functions. This allows for greatly reduced power
consumption, yet preserves the radio’s ability to be
quickly brought on line. See Section 4.6, Using the
Radio’s Sleep Mode (beginning on Page 25) for details.
13 -- Unused.