
Pluto User Manual A4
www.diamondsystems.com
Page
27
4.13 Utility Signals (JFRT1)
This connector provides interface signals for use with
various “front panel” switches and indicators.
4.14 COM2 RS-422/485 Interface (JCOM1)
Connector JCOM
1 provides access to the COM2 serial port’s transmit and receive data when the port is
configured for either RS-422 or RS-
485 serial protocols. The signals present on each of the connector’s four pins
for these two modes are listed in the table below. COM2
’s serial protocol mode is selected using configuration
jumpers located at position JRS2 on the Pluto Baseboard. When the port is configured for RS-232 mode, its
interface appears at connector COMA instead of JCOM1.
RESET+
1
2
RESET-
PO
3
4
POWER_LED-
5
6
HDD_LED-
7
8
SPEAKER-
NC
9
I0
GND
Signal Name
Signal Function
Direction
RESET
Act
ive low reset input; connects to “Power
Good” input on ETX CPU module
Input
POWER_LED
Power on indicator
Output
HDD_LED
HDD access indicator
Output
SPEAKER
PC speaker output (connects in parallel
with onboard buzzer)
Output
Pin
RS-422 Mode Signal
RS-485 Mode Signal
1
TX+
DATA+
2
TX-
DATA-
3
RX+
N/C
4
RX-
N/C