Manuals

Hardware Configuration Features: Dell™ Precision™ WorkStation 410 Desktop Systems

Overview

This appendix provides specific information about the jumpers on your system board and the input/output (I/O) ports and connectors on the back panel of your computer. It also provides some basic information on jumpers and switches, a listing of interrupt request (IRQ) assignments, and memory maps.

Jumpers and Switches-A General Explanation

Jumpers and switches provide a convenient and reversible way of reconfiguring the circuitry on a printed circuit board. When reconfiguring your system, you may need to change jumper settings on your system board; you may also need to change jumper and/or switch settings on expansion cards or drives.

Jumpers

Jumpers are small blocks on a circuit board with two or more pins emerging from them. Plastic plugs containing a wire fit down over the pins. The wire connects the pins and creates a circuit.

To change a jumper setting, pull the plug off its pin(s) and carefully fit it down onto the pin(s) indicated.

CAUTION: Make sure your system is turned off before you change a jumper setting. Otherwise, damage to your system or unpredictable results may occur.

A jumper is referred to as open or unjumpered when the plug is pushed down over only one pin or if there is no plug at all. When the plug is pushed down over two pins, the jumper is referred to as jumpered. The jumper setting is often shown in text as two numbers, such as 1-2. The number 1 is printed on the circuit board so that you can identify each pin number based on the location of pin 1.

Figure B-1 shows the location and default settings of the jumper blocks on your system board. See Table B-1 for the designations, default settings, and functions of your system's jumpers.

Switches

Switches control various circuits or functions in your computer system. The switches you are most likely to encounter are dual in-line package (DIP) switches, which are normally packaged in groups of two or more switches in a plastic case. Two common types of DIP switches are slide switches and rocker switches (see the following illustration).

Each of these switches has two positions, or settings (usually on and off). To change the setting of a slide switch, use a small, pointed object such as a small screwdriver or a straightened paper clip to slide the switch to the proper position. To change the setting of a rocker switch, use the screwdriver or paper clip to press down on the appropriate side of the switch. In either case, do not use a pen, pencil, or other object that might leave a residue on the switch.

Figure B-1. System Board Jumpers

Table B-1. System Board Jumpers Settings

Jumper	Setting	Description
RSVD2		Reserved (do not install jumper plug).
RSVD1		Reserved (do not install jumper plug).
450MHZ*		Jumpered when the microprocessor's internal speed is 450 MHz.
400MHZ*		Jumpered when the microprocessor's internal speed is 400 MHz.
350MHZ*		Jumpered when the microprocessor’s internal speed is 350 MHz.
300MHZ		Reserved (do not install jumper plug).
TOWER		Reserved (do not install jumper plug).
BIOS		Reserved (do not install jumper plug).
PSWD		Password features enabled. Password features disabled.
NICCFG		Reserved (do not install jumper plug).
* One set of the speed jumper pins must have a jumper plug installed; otherwise, the system will operate at an undetermined speed.
NOTE: For the full name of an abbreviation or acronym used in this table, see the Glossary.

System Board Labels

Table B-2 lists the labels for connectors and sockets on your system board and gives a brief description of their functions. System Board Connectors and Sockets

Table B-2. System Board Connectors and Sockets

I/O Ports and Connectors

The I/O ports and connectors on the back panel of your computer are the gateways through which your computer system communicates with external devices, such as a keyboard, mouse, printer, and monitor. Figure B-2 identifies the I/O ports and connectors for your computer.

Figure B-2. I/O Ports and Connectors

Serial and Parallel Ports

The two built-in serial ports use 9-pin D-subminiature connectors on the back panel. These ports support devices such as external modems, printers, plotters, and mice that require serial data transmission (the transmission of data one bit at a time over one line).

Most software uses the term COM (for COMmunications) plus a number to designate a serial port (for example, COM1 or COM2). The default designations of your computer's built-in serial ports are COM1 and COM2.

The built-in parallel port uses a 25-pin D-subminiature connector on the computer's back panel. This I/O port sends data in parallel format (where eight data bits, or one byte, are sent simultaneously over eight separate lines in a single cable). The parallel port is used primarily for printers.

Most software uses the term LPT (for Line PrinTer) plus a number to designate a parallel port (for example, LPT1). The default designation of your computer's built-in parallel port is LPT1.

Port designations are used, for example, in software installation procedures that include a step in which you identify the port to which your printer is attached, thus telling your software where to send its output. (An incorrect designation prevents the printer from printing or causes scrambled print.)

Adding an Expansion Card Containing Serial or Parallel Ports

Your computer system has an autoconfiguration capability for the serial ports. This feature lets you add an expansion card containing a serial port that has the same designation as one of the built-in ports without having to reconfigure the card. When the computer detects the duplicate serial port on the expansion card, it remaps (reassigns) the built-in port to the next available port designation.

Both the new and the remapped COM ports share the same IRQ setting, as follows:

COM1, COM3: IRQ4 (shared setting)
COM2, COM4: IRQ3 (shared setting)

These COM ports have the following I/O address settings:

COM1: 3F8h
COM2: 2F8h
COM3: 3E8h
COM4: 2E8h

For example, if you add an internal modem card with a port configured as COM1, the computer then see s logical COM1 as the address on the modem card. It automatically remaps the built-in serial port that was designated as COM1 to COM3, which shares the COM1 IRQ setting. (Note that when you have two COM ports sharing an IRQ setting, you can use either port as necessary but you may not be able to use them both at the same time.) If you install one or more expansion cards with serial ports designated as COM1 and COM3, the corresponding built-in serial port is disabled, as described in "Serial Port 1 and Serial Port 2".

Before adding a card that remaps the COM ports, check the documentation that accompanied your software to make sure that the software can be mapped to the new COM port designation.

To avoid autoconfiguration, you may be able to reset the expansion card's jumpers or switches so that its port designation changes to the next available COM number, leaving the designation for the built-in port as is. Alternatively, you can disable the built-in ports through the System Setup program. The documentation for your expansion card should provide the card's default I/O address and allowable IRQ settings. It should also provide instructions for readdressing the port and changing the IRQ setting if necessary.

The built-in parallel port has autoconfiguration capability through the System Setup program. That is, if you set the parallel port to its automatic configuration and add an expansion card containing a port configured as LPT1 (IRQ7, I/O address 378h), the system automatically remaps the built-in parallel port to its secondary address (IRQ5, I/O address 278h). If the secondary port address is already being used, the built-in parallel port is turned off. For more information, see " Parallel Port".

For general information on how your operating system handles serial and parallel ports as well as for more detailed command procedures, see your operating system documentation.

Serial Port Connectors

If you reconfigure your hardware, you may need pin number and signal information for the serial port connectors. Figure B-3 illustrates the pin numbers for the serial port connectors, and Table B-3 lists and defines the pin assignments and interface signals for the serial port connectors.

Figure B-3. Pin Numbers for the Serial Port Connectors

Table B-3. Pin Assignments for the Serial Port Connectors

Parallel Port Connector

If you reconfigure your hardware, you may need pin number and signal information for the parallel port connector. Figure B-4 illustrates the pin numbers for the parallel port connector, and Table B-4 lists and defines the pin assignments and interface signals for the parallel port connector.

Figure B-4. Pin Numbers for the Parallel Port Connector

Table B-4. Pin Assignments for the Parallel Port Connector

External SCSI Connector

The 68-pin external small computer system interface (SCSI) connector on the system back panel supports external Ultra SCSI devices such as scanners, ZIP drives, and optical drives.

If you reconfigure your hardware, you may need pin number and signal information for the external SCSI connector. Figure B-5 illustrates the pin numbers for the external SCSI connector, and Table B-5 lists and defines the pin assignments and interface signals for the external SCSI connector.

Figure B-5. Pin Numbers for the External SCSI Connector

Table B-5. Pin Assignments for the External SCSI Connector

Keyboard and Mouse Connectors

Your system uses a Personal System/2 (PS/2)-style keyboard and supports a PS/2-compatible mouse. Cables from both devices attach to 6-pin miniature Deutsche Industrie Norm (DIN) connectors on the back panel of your computer.

A PS/2-compatible mouse works identically to an industry-standard serial mouse or bus mouse except that it has its own dedicated connector, which frees up both serial ports and does not require an expansion card. Circuitry inside the mouse detects the movement of a small ball and relays the direction to the computer.

Mouse driver software can give the mouse priority with the microprocessor by issuing IRQ12 whenever a new mouse movement is made. The driver software also passes along the mouse data to the application program that is in control.

Keyboard Connector

If you reconfigure your hardware, you may need pin number and signal information for the keyboard connector. Figure B-6 illustrates the pin numbers for the keyboard connector, and Table B-6 lists and defines the pin assignments and interface signals for the keyboard connector.

Figure B-6. Pin Numbers for the Keyboard Connector

Table B-6. Pin Assignments for the Keyboard Connector

Mouse Connector

If you reconfigure your hardware, you may need pin number and signal information for the mouse connector. Figure B-7 illustrates the pin numbers for the mouse connector, and Table B-7 lists and defines the pin assignments and interface signals for the mouse connector.

Figure B-7. Pin Numbers for the Mouse Connector

Table B-7. Pin Assignments for the Mouse Connector

Video Connector

For information on your video connector, see the manufacturer's specifications that accompanied your video card.

NIC Connector

Your system contains an RJ45 connector (see Figure B-8) on the back panel for attaching an unshielded twisted pair (UTP) Ethernet cable, which is used in 10BASE-T and 100BASE-TX networks. The network interface controller (NIC) provides all the functions normally handled by a separate network expansion card. To connect your system to and configure it for use on an Ethernet network, see "Using the Network Interface Controller."

Figure B-8. NIC Connector

USB Connectors

Your system contains two Universal Serial Bus (USB) connectors for attaching USB-compliant devices. USB devices are typically peripherals such as keyboards, mice, printers, and computer speakers.

CAUTION: Do not attach a USB device or a combination of USB devices that draw a maximum current over 500 milliamperes (mA) per channel at +5 volts (V). Attaching devices that exceed this threshold may cause the USB ports to shut down. See the documentation that accompanied the USB devices for their maximum current ratings.

If you reconfigure your hardware, you may need pin number and signal information for the USB connectors. Figure B-9 illustrates the pin numbers for the USB connectors, and Table B-8 lists and defines the pin assignments and interface signals for the USB connectors.

Figure B-9. Pin Numbers for the USB Connectors

Table B-8. Pin Assignments for the USB Connectors

Microphone Jack

The microphone jack (see Figure B-10) can be used to attach a standard personal computer microphone. Connect the audio cable from the microphone to the microphone jack. The microphone input is a mono source with maximum signal levels of 89 millivolts root mean squared (mVrms).

Figure B-10. Microphone Jack

Line-Out Jack

The line-out jack (see Figure B-11) can be used to attach most computer speakers. The line-out jack is amplified, so speakers with integrated amplifiers are not required. Connect the audio cable from the speakers to this jack.

Figure B-11. Line-Out Jack

Line-In Jack

The line-in jack (see Figure B-12) can be used to attach record/playback devices such as cassette players, CD players, and VCRs. Connect the line-out cable from any of these devices to the line-in jack on the back of your computer.

Figure B-12. Line-In Jack

Interrupt Assignments

Problems can arise if two devices attempt to use the same IRQ line. To avoid this type of conflict, check the documentation for the default IRQ line setting for each installed device. Then consult Table B-9 to configure each device for one of the available IRQ or other lines.

NOTE: Interrupts for the on-board sound, NIC, and both SCSI channels are assigned dynamically by the system basic input/output system (BIOS).

Table B-9. Interrupt Assignments

Memory Allocations

A microprocessor and programs operating under MS-DOS (real-mode operation) can address only 1 megabyte (MB) (1024 kilobytes [KB]) of system memory. This area is divided into conventional memory (sometimes called base memory) and upper memory. All system memory above this 1 MB is called extended memory and cannot be directly addressed by MS-DOS-based programs without the aid of some special memory-managing software.

Table B-10 provides a map of the conventional memory area. When the microprocessor or a program addresses a location within the conventional memory range, it is physically addressing a location in main memory, which is the only main memory it can address under MS-DOS.

Table B-10. Conventional Memory Map

Table B-11 provides a map of the upper memory area. Some of these addresses are dedicated to various system devices, such as the system BIOS. Others are available for use by expansion cards and/or an expanded memory manager (EMM). When the microprocessor or a program addresses a location within the upper memory area, it is physically addressing a location within one of these devices.

Table B-11. Upper Memory Map