Chapter 1: Product Overview 1-13
Serial Ports
The Summa POS Motherboard provides two RS-232 ports (9-pin D-
shell connectors, Ports 1 and 2) directly on the Motherboard and
supports two additional RS-232 ports. Ports 3 and 4 require an optional
harness connection to the Motherboard. Ports 1 and 3 can be supplied
with +12 V DC on Pin 9 when properly set up in the BIOS. The total
power drawn by Ports 1 and/or 3 must be no greater than 1 amp at +12
V DC. Refer to the following table for RS-232 pinout information.
The BIOS provides flexibility in mapping resources. However, a fully-
loaded system (2 PCMCIA cards that require IRQs, four serial ports in
use, USB in use, parallel port in use, and MSR) may not have enough
available IRQs to support all serial ports. Use a USB serial port
expander to overcome this PC architecture limitation.
RS-232 DB-9 Male Connector Pinout
Pin Port A Port B
1 DCD DCD
2 RXD RXD
3 TXD TXD
4 DTR DTR
5 GND GND
6 DSR DSR
7 RTS RTS
8 CTS CTS
9 RI or +12*
RI
* If Port 1 or 3 is powered, pin 9 will be +12 V.
Hardware Monitor
The hardware monitor generates an interrupt to the system whenever
any of the internal voltages used by the system processor goes above or
below the acceptable operating range. An interrupt is also generated
when the temperature of the Processor exceeds safe levels. Software
can use this indication to slow or stop the system and/or force a reset.
