Chapter 2. System Board Features
Parallel Port
One parallel port is integrated into the system board. Support for extended capabilities port (ECP),
enhanced parallel port (EPP), and standard parallel port (SPP) modes is provided. These modes are
selected through the Configuration/Setup Utility program, with the default mode set to SPP. The ECP and
EPP modes are compliant with IEEE 1284.
The following table shows the typical system resource assignments for the parallel port.
Note: The default setting for the parallel port is LPT1. When the computer is started, the resource
assignments are subject to change during POST.
The external interface for the parallel port is a 25-pin, female, D-shell connector. For information on
connector pin assignments, see “Parallel Port Connector” on page 49.
Serial Ports
The serial port subsystem consists of two universal asynchronous receiver/transmitters (UARTs) that are
PC16550A- and NS16450-compatible. The serial ports include a 16-byte data first-in first-out (FIFO)
buffer and have programmable baud rate generators. The UARTs function independently of one another,
and both can be used in normal mode, which is inclusive of modem control circuitry. UART2 function is
determined at boot time via the Configuration/Setup Utility program and can only be altered by changing
setup and rebooting the computer.
The following table shows the typical system resource assignments for the serial ports.
The default setting for serial port 1 is COM1. For serial port 2, the default setting is COM2. When the
computer is started, the resource assignments are subject to change during POST.
The external interface for the serial ports consists of two, 9-pin, male, D-shell connectors. For information
on connector pin assignments, see “Serial Port Connectors” on page 50.
Table 3. System Resource Assignments for the Parallel Port
Configuration ROM RAM I/O Address (Hex) IRQ DMA
LPT1 None None 03BC–03BE 7 3
2
LPT2 None None 0378-037F 5 3
2
LPT3 None None 0278-027F 3
2
Table 4. System Resource Assignments for the Serial Ports
Configuration ROM RAM I/O Address (Hex) IRQ DMA
COM1 None None 03F8-03FF 4 None
COM2 None None 02F8-02FF 3 None
COM3 None None 0220-0227, 02E8-02EF,
0338-033F, 03E8-03EF
4 None
COM4 None None 0220-0227, 02E8-02EF,
0338-033F, 03E8-03EF
3 None
2
ECP/EPP mode only.
Chapter 2. System Board Features
13
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