26
SD Series Technical Manual
MDS 05-4846A01, Rev. H
Table 8. COM2 Pin Descriptions—Radio in RS-232 Mode
Pin
Number
Radio
Input/
Output
Pin Description
1
OUT
DCD (Data Carrier Detect/Link)
—A high indicates signal
received.
2
OUT
RXD (Received Data)
—Supplies received data to the
connected device.
3
IN
TXD (Transmitted Data)
—Accepts TX data from the
connected device.
4
IN
Sleep Mode Input
—Grounding this pin places the radio in a
low power consumption mode.
5
--
Signal Ground—
Connects to ground (negative supply
potential) on chassis.
6
OUT
Alarm Output (DSR)—
Behavior is user-configurable.
Default
behavior:
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.
7
IN
RTS (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 another
connected radio when RF data arrives (CTS KEY).
9
--
Reserved—User I/O for special applications
Table 9. COM2 Pin Descriptions—Radio in RS-485 Mode
Pin
Number
Input/
Output
Pin Description
1
OUT
Carrier Detect/Link
—A high indicates signal received.
2
OUT
TXD-/TXA
(Transmitted Data -)—Inverting driver output.
Supplies received payload data to the connected device.
3
IN
RXD-/RXA
(Received Data -)—Inverting receiver input.
Accepts payload data from the connected device.
4
IN
Sleep Mode Input
—Grounding this pin places the radio in a
low power consumption mode.
5
--
Ground
—Connects to ground (negative supply potential) on
the radio’s PC board.
6
OUT
Alarm Output—
Behavior is user-configurable.
Default
behavior:
A high on this pin indicates an alarm condition; a low
indicates normal operation.
7
IN
RXD+/RXB
(Received Data +)— Non-inverting receiver input
8
OUT
TXD+/TXB
(Transmitted Data +)
—
Non-inverting driver output.
9
--
Reserved—User I/O for special applications
