User's Manual

14 MDS SD9 Startup Guide 05-xxxxA01, Rev. 01
NOTE: The radio is hard-wired as a DCE device.
NOTE: Additional information on Analog Mode operation (including
cable wiring details) is contained in the Reference Manual.
Table 5. COM2 Pin Descriptions—RS/EIA-232
Pin
Number
Input/
Output Pin Description
1 OUT DCD (Data Carrier Detect/Link)—A low indicates
signal received.
Digital Modem Selections: Digital carrier detect
Analog Modem Selections: Squelch indicator
2 OUT RXD (Received Data)—Supplies received data to
the connected device.
3INTXD (Transmitted Data)—Accepts TX data from the
connected device.
4INSleep Mode Input—Grounding this pin turns off
most circuits in a remote radio. This allows for greatly
reduced power consumption, yet preserves the
radio’s ability to be quickly brought on line. (See
Using the Radio’s Sleep Mode” for details.)
5--Signal Ground—Connects to ground (negative
supply potential) on chassis.
6 OUT Alarm Output (DSR)—An RS-232 high/space
(+5.0 Vdc) on this pin indicates an alarm condition.
An RS-232 low/mark (–5.0 Vdc) indicates normal
operation. This pin may be used as an alarm output.
(See Reference Manual.)
7INRTS (Request-to-Send)—Keys the transmitter.
8 OUT CTS (Clear-to-Send)—Goes “high” after the
programmed CTS delay time has elapsed (DCE), or
keys an attached radio when RF data arrives (CTS
KEY).
9 -- Reserved—User I/O for special applications