Purchasing and Installing an

Ethernet Card for an IBM PC

or Compatible

Table of Contents

II. Guidelines for Installing an Ethernet Card

Appendix--PC System Resources Commonly Used by Ethernet Cards

I. Things to Consider When Purchasing an Ethernet Card

1. Media Support. Before you buy an Ethernet card for a PC, you need to consider how that PC will be connected to the network. In particular, the Ethernet card must have the appropriate connector to attach it to the specific type of cable or media in use on your network. The following media are used in building Ethernets on this campus:

• 10/100BaseT (Unshielded Twisted Pair, RJ-45). If the PC will be connected to a b-jack (a data jack on the same wallplate as the regular telephone jack, usually beneath it), the card must support the standard specification for running Ethernet over twisted pair wiring called 10BaseT. 10BaseT Ethernet cards always have a port that looks like a phone jack that accommodates an RJ-45 (8 pin) connector. The 10BaseT standard has a cable distance limit of 100 meters (roughly 300 feet) from repeater to Ethernet card. The maximum number of devices per network is 1024.

• 10Base2 (Thin Coax, BNC). If the PC will be connected to a cluster of PCs daisy-chained with thin coaxial cable, the Ethernet card must have a BNC port. The 10Base2 standard has a cable distance limit of 185 meters (roughly 600 feet) for a single unrepeated segment of thin coax, with a .5 meter minimum between devices. The maximum number of devices per segment is 30 and the maximum per network is 1024. Each end of the segment must be properly terminated.

  There are two options for connecting thin coax cards to a 10BaseT repeater. If the card has an AUI port, you can buy an AUI-RJ-45 transceiver (at $30-$40), or if you have a thin segment with multiple nodes attached, it might make more sense to buy a 10Base2-10BaseT media converter (roughly $185).

• 10Base5 (Thick Coax, AUI). If the PC will be connected to a thick Ethernet backbone, you will need a card with an AUI port and an external transceiver, which connects the AUI port to the thick Ethernet cable. The 10Base5 standard has a cable distance limit of 500 meters (roughly 1500 feet) for a single unrepeated segment of thick coax, with a 1.5 meter minimum between devices. The maximum number of devices per segment is 100 and the maximum per network is 1024. Each end of the segment must be properly terminated. Thick Ethernet is somewhat unusual on the UIUC campus.

• Today three types of Ethernet cards are common: 1) the so-called 3-in-1 or combo card. This card has a 10BaseT, BNC, and AUI port and can be used for any of the media types described above; 2) A coax card, which typically has both thin (BNC) and thick (AUI) coax ports; and 3) a 10BaseT card, which usually has an RJ-45 port for twisted pair connections and an AUI port for thick Ethernet connections.

• You can't go wrong with a combo card, but they tend to be slightly more expensive. Combo cards are also strongly recommended for PCs in a building network with both twisted pair and thin Ethernet connections, because the PC can be easily moved to a new location without changing the Ethernet card. Before buying a 10BaseT or coax card, make sure that it will be appropriate for the type of connection you want to make.

2. Bus Type. The channel that allows the hardware components within and external to the PC to communicate with one another is called the bus. There are many different PC bus standards. Some are open specifications used by many different vendors and others are proprietary. When purchasing a card, it must conform to the bus type native to the computer. The following six bus types are common today:

• PC. This is the 8-bit bus characteristic of the original IBM PC, XT, and clones with an 8086 or 8088 microprocessor. It is the slowest of the PC bus types.

• Micro Channel Architecture (MCA). This is IBM's proprietary bus, which is used in all IBM PS/2 models 50 and above as well as IBM's Premier line. Micro Channel machines can only use Ethernet cards specifically designed for the Micro Channel bus.

• Industry Standard Architecture (ISA). The original IBM AT, IBM's new ValuePoint line, and most PC clones conform to the ISA standard, as do certain models in the IBM PS/2 family (e.g., model 30, model 35, model 30 286). ISA machines can use 8-bit PC or 16 bit ISA Ethernet cards (for more information on 8- versus 16-bit cards, see the next section).

• Extended Industry Standard Architecture (EISA). The EISA standard is used by many clone manufacturers for high-performance machines with an 80386 microprocessor or higher. EISA machines can accept EISA, ISA and PC bus Ethernet cards. EISA cards are faster, but considerably more expensive than ISA cards. An EISA card would be appropriate for a heavy traffic machine such as an EISA LAN server. EISA expansion slots are downwardly compatible with PC- and ISA-bus adapter cards.

• VESA Local Bus. VESA local bus is a high-speed bus, standardized by the Video Electronics Standards Association (VESA), that runs at a higher speed than ISA, EISA, and MicroChannel buses. Data is transferred at the clock speed of the CPU, using the same channel that is used to move data between the CPU and memory . VESA local bus architecture, a modification of the ISA standard, is usually limited to one or two of the several expansion slots in a PC. The remaining slots are plain ISA slots. Local bus expansion slots support local bus, ISA, and PC adapter cards. VESA locals bus Ethernet cards are much faster than EISA, ISA, and PC bus cards and are well-suited to LAN servers.

• PCI Local Bus. Peripheral Component Interconnect (PCI) local bus is a new high-speed bus, standardized by Intel Corporation, that runs at a higher speed than ISA, EISA, and Micro Channel buses. The PCI bus is actually isolated from the CPU bus, which means that it can be used with processors much faster than those supported by the VESA standard. Some, but not all, PCI local bus expansion slots also support ISA and PC adapter cards. PCI locals bus Ethernet cards are much faster than EISA, ISA, and PC bus cards and are well-suited to LAN servers.

3. Data Path Size. The size of the data path for a particular bus is defined by how many bits can be transferred in parallel from an adapter card to the CPU. Different models of PCs and compatibles support different size data paths. Typically 8086 and 8088 machines have an 8-bit bus; 80286 and 80386SX machines have a 16-bit bus; and 80386 machines (and higher) have a 32-bit bus. The following generalizations can be made:

• All 8086 and 8088 PCs (original IBM PC, XT, and clones thereof) can only use 8-bit Ethernet cards because the bus is strictly an 8-bit bus. Some 16-bit cards are designed to fit into either an 8- or 16-bit slot. Such cards can be used in a 8086/8088 PC, but they are more expensive and their full potential cannot be realized.

• All ISA PCs and clones with an 80286 processor or higher can use either an 8- or a 16-bit ISA Ethernet card. In order to use a 16-bit card, a 16-bit slot must be available. Sixteen-bit cards are faster and support hardware interrupts 2 through 15, whereas 8-bit cards only support interrupts 2 through 7. For more information on hardware interrupts, see sections II.3 and Appendix A.1.

• EISA computers with an 80386 processor or higher usually have several 32-bit EISA slots. These slots support 32-bit EISA bus Ethernet adapters as well as 16-bit ISA bus and 8-bit PC bus cards.

• VESA local bus systems with an 80486 processor or higher usually have one or two 32-bit VESA local bus slots and several ISA slots. An 8- or 16-bit ISA card can be used in any slot, or, for better performance, a 32-bit local bus card can be used in the local bus slot.

• PCI local bus computers with an 80486 processor or higher usually have several 32-bit local bus slots and several 16-bit ISA slots. Some also have slots that can support both PCI and ISA. An 8- or 16-bit ISA card can be used in a slot that support ISA, or a 32-bit PCI card can be used in a PCI slot.

• MicroChannel architecture (MCA) computers accept only MicroChannel bus cards. MCA computers with an 80386 processor or higher and an available 32-bit slot can use a 16- or 32-bit Ethernet card. MCA computers with a 286 or 386SX processor (such as the IBM PS/2 model 50, 50Z, and 55) can only use a 16-bit card.

4. Network Software Support:When purchasing an Ethernet card, verify that the card ships with the appropriate drivers for the operating system you plan to use (e.g., DOS, OS/2, Windows NT, Windows for Workgroups, Windows 95, etc.) and the network services you plan to access (e.g., Netware, Windows NT, LAN Manager, Banyan Vines, TCP/IP, etc.). If you plan to install the card in a DOS system, it is extremely important that the card ship, at the very least, with ODI and NDIS 2.x and 3.x drivers. If the Ethernet card will be installed in a LAN server, you may need additional drivers for the card.

Safe Bets: There are two well-known Ethernet hardware manufacturers whose cards are widely used across campus: Standard Microsystems Corporation (SMC, formerly Western Digital) and 3Com. Both companies have been making Ethernet cards for a long time and probably won't disappear in the near future. Clone Ethernet cards conforming to the SMC, 3Com, or Novell hardware specifications also exist, but buying a card from a fly-by-night manufacturer may not be in your long-term best interest, even if such cards are significantly less expensive.

II. Guidelines for Installing Ethernet Cards

1. Open up the package containing the card and review the accompanying documentation. The first time you install a particular model, it's a good idea to read most of the manual. If you've already installed the same card many times over, you may only need to refer to the documentation when you have a question.

2. Unplug the computer and monitor, and remove the cover from the system unit.

Note for MicroChannel computers: If you are installing a MicroChannel card, you must boot with the Reference diskette and install an Option diskette before or after you install the card. The option diskette provides the computer with information about the card. If you install the card before installing the option diskette, you will see a configuration error when you power on the machine. Read the card's documentation for details.

3. Determine configuration options for the card. Use the documentation that came with the card to find out what the default hardware configuration settings are. Any settings that conflict with another device in the computer must be changed.

The hardware settings that can be changed vary from model to model, but at the very least, most cards require the user to specify the following items:

• Hardware Interrupt ReQuest line (IRQ) (for more information see Appendix A.1)
• Base I/O Address (for more information see Appendix A.2)
• Base Shared RAM Address (for more information see Appendix A.4)

Other configuration options that may need attention are:

• DMA Channel (for more information see Appendix A.3)
• Media Type (AUI/DIX/10Base5/Thick; BNC/10Base2/Thin; RJ45/10BaseT/UTP) (for more information see section I.1)
• RAM Buffer Size (for more information see Appendix A.4)

For more information on what each parameter means, and recommended settings, see Appendix A.

4. Write down configuration settings. Once you determine the best settings for the interrupt, I/O base address, and shared memory base address, write them down. You will be asked to provide this information when you configure your network software to work with the card. You may also want to write down the Ethernet address of the card, six two-digit hexadecimal numbers that uniquely identify the adapter. If you maintain a permanent log or database with information about each workstation on your network, add the information you just recorded to this database. Knowing the configuration and address of each Ethernet adapter on your network can be invaluable when troubleshooting problems.

5. Change configuration manually or with software. Make changes as appropriate so that the card will not conflict with the target system. This may involve moving jumpers (tiny, square pieces of plastic with copper inside that make or break connections between copper pins on the card), setting DIP switches, or running configuration software. EISA, PCI, and Micro Channel cards are configured solely by software. V-LB and ISA cards may offer the option of software or hardware configuration.

• If the card must be configured manually (by moving DIP switches or jumpers), make the necessary adjustments, before inserting it into an empty adapter slot. Then reassemble and power on the computer.

• If the card will be configured with software, insert it into an empty adapter slot. Then reassemble and power on the computer and run the configuration software.

6. Run diagnostic software. If diagnostic software came with the card, run it after the card is installed to ensure proper installation and configuration.

7. Connect computer to network. Use an appropriate cable to connect the computer to the network.

• If the card is a 10/100BaseT card, run a patch cable from the Ethernet card to the b-jack on the wall. Then, make a connection between the port on the patch panel that corresponds to the b-jack and an empty port on the Ethernet repeater. Check to make sure that the link light is lit on both the repeater and the Ethernet card (the link light is only illuminated when the computer is powered on).

• If the card is a thin coax card, connect the card to your coax run with a T connector. Add a terminator to one end of the T connector if this is the last computer in the run. If not, connect a coax segment to both ends of the T connector.

8. Reconfigure memory managers. If an expanded memory manager such as MS DOS's emm386.exe, QuarterDeck's QEMM, Qualitas's 386 to the MAX, etc., is installed on the target system, the memory manager must be reconfigured so that it does not take control of the memory range used for shared memory on the Ethernet card. Normally, expanded memory managers are loaded at the beginning of the config.sys file and have an option for excluding address ranges from use by the manager.

For example, if you just installed an Ethernet card with 16K of shared RAM and configured the card and the driver to use the base shared RAM address of d000, you would have to exclude the range d0000-d3fff from use by the memory manager. The memory manager supplied with DOS 5.0 and higher (emm386.exe) uses an x option for this purpose. To exclude the memory range used by the Ethernet card, the line that loads emm386.exe would look something like this:

		device=c:\dos\emm386.exe x=d000-d3ff

Note: The emm386.exe utility requires that memory addresses be expressed in a special form of hexadecimal notation called paragraph notation. In paragraph notation the last digit is dropped, and the address refers to an entire 16 byte block of memory (called a paragraph). In the above example, the excluded address range starts at the lower boundary of the first paragraph listed (i.e., d0000) and ends at the upper boundary second paragraph listed (i.e., d3fff). Check the documentation for the specific syntax required to exclude a range from use by your memory manager. Then, load your config.sys file into a text editor and make the necessary modifications to the file.

9. Install network software. Install the appropriate network driver(s) for the card using the parameters you wrote down. See the guide called Packet Drivers for IBM PCs and Clones for more information on installing network drivers. Then install one or several TCP/IP applications and test your total configuration.

10. C'est finis? If it all works, congratulations, you're done. If it doesn't--sigh--review all error messages and start troubleshooting.

Appendix A

PC System Resources Commonly Used by Ethernet Cards

1. Hardware Interrupt (IRQ, Interrupt ReQuest) - IRQs are used by devices installed in the PC to get the attention of the processor by literally interrupting the current process. In most cases, it is not possible or desirable for two or more installed devices to use the same IRQ, even if the devices are not used at the same time. Interrupt conflicts are frequently the cause of malfunctioning Ethernet cards. When assigning an IRQ to an Ethernet card, you must take into consideration both the type of PC (8086/88 bus vs. 80286+) and the IRQs of other devices installed in the computer. Table A-1 below shows IRQ usage on a 8086/88 machine (PC) and on a 80286 machine (AT) or higher.

Table A-1 PC/AT Interrupt Usage

PC/XT (8086/88)	IRQ #	AT and above (80286+)
timer	0	timer
keyboard	1	keyboard
frequently available	2	frequently available (actually redirected to IRQ 9)
COM2 (available if no COM2)	3	COM2 (available if no COM2)
COM1	4	COM1
hard disk controller	5	LPT2 (available if no LPT2)
floppy disk controller	6	floppy disk controller
LPT1	7	LPT1
Not Applicable	8	real-time clock
Not Applicable	9	used for devices assigned to IRQ 2
Not Applicable	10	frequently available
Not Applicable	11	frequently available
Not Applicable	12	PS/2 mouse
Not Applicable	13	math co-processor
Not Applicable	14	hard disk controler
Not Applicable	15	frequently available

Note that no device in a PC/XT class machine may be configured to use an IRQ higher than 7. Thus even if an Ethernet card can be set to use IRQ 10, 11, or 15, such settings can only be used in an 80286 machine or higher. Note also that while Table A-1 shows the commonly used interrupts, there may be devices in your PC configured to use an IRQ that is labeled "frequently available" in the table. Common interrupt-driven devices include SCSI adapters, CD ROM drives, mice, internal modems, memory expansion cards with COM and/or LPT ports, optical scanners, some EGA or VGA adapters.

By looking at the existing integrated devices and ports along with adapter cards, try to determine which hardware interrupts are already in use. Look for:

• Serial Ports and/or Devices -- If the computer only has one serial device or port, then IRQ 4 is used. If it has two or more serial devices or ports, IRQ 4 and 3 are probably in use. Serial ports are typically male 9- or 25-pin D-shaped connectors (DB9 and DB25) located on an adapter board or integrated on the motherboard (see illustration below). The following types of external devices often use a serial port: modem, serial mouse, bus mouse card, and plotters or printers (printers are usually attached to parallel ports, but occasionally they are attached to serial ports, especially laser printers). Internal modems also use either IRQ 4 or 3.

  

• If there is only one serial port or device in the computer, it may still be configured to use IRQ 3 instead of 4. If you have any question about which IRQ is being used, consult the documentation for the adapter card. Note: Even if there is no device plugged into a second serial port, its IRQ still may may not be available for use by another device.

• Parallel Ports and/or Devices -- Parallel ports are usually used for printers but they can also be used for external tape backup devices, external Ethernet adapters, and other peripherals. The first parallel port (LPT1) uses IRQ 7, and, if there is a second parallel port, it uses IRQ 5. Parallel ports on adapter boards or on the motherboard are characterized by a female 25-pin (DB25) connectors (see illustration below). Note: Even if there is no device plugged into the second parallel port, it still uses IRQ 5 unless you disable the port.

  

• Other Interrupt-Driven Devices -- there are a variety of additional internal and external devices that may be interrupt driven. These include: hard drive, EGA or VGA video adapters (normally such adapters do not use an interrupt, but occasionally they do), optical scanners, built-in mouse ports, CD ROM drives, devices using a SCSI adapter, math coprocessor, etc. Some of these devices use fixed IRQs and others are configurable. Below are schematics of common PC adapter ports. Being able to identify adapters by sight will help you to determine which interrupts are available:

  

  

2. Base I/O Address - An address that the processor can use to communicate directly with the adapter board. The I/O address assigned to the Ethernet card must not be used by any other device installed in the PC. Typically the I/O address for the card is assigned to an unused port somewhere within the range 0x200 and 0x3ff. Common choices are 0x240, 0x280, 0x2a0, 0x2c0, 0x300, and 0x340. Note: SMC MicroChannel cards use I/O addresses outside of this range.

3. DMA channel - Direct Memory Access channels allow for direct, high-speed communication between the Ethernet card and RAM. Two devices can share the same DMA channel as long as they are not used simultaneously. Not all Ethernet card brands and models use DMA channels. Table A-2 on the next page shows DMA channel usage on a 8086/88 machine (PC) and on a 80286 machine (AT) or higher.

Table A-2 PC/AT DMA Channel Usage

PC/XT (8086/88)	DMA Channel #	AT and above (80286+)
refresh dynamic RAM	0	frequently available (16 bit only)
frequently available	1	frequently available (8 bit only)
floppy disk controller	2	floppy disk controller
hard disk controller	3	frequently available (8 bit only)
Not Applicable	4	cascade of 0-3 to microprocessor
Not Applicable	5	frequently available (16 bit only)
Not Applicable	6	frequently available (16 bit only)
Not Applicable	7	frequently available (16 bit only)

4. Base Address for Shared Memory - Most Ethernet cards have from 8K to 32K of on-board RAM for buffering incoming and outgoing data. Typically this memory does not have a fixed address and can be assigned to an address space somewhere within the 640K to 1MB range. The RAM address range assigned to the card must not be used by any other device installed in the computer. Table A-3 on the next page shows the address space between 640K and 1 Megabyte in 8K increments and identifies common usage for various address blocks.

Although it appears that very little of the High Memory address space is available for the on-board RAM on the Ethernet card, the table should not be taken too literally. The C0000-CFFFF range is commonly available on 80286 machines or higher with 8-bit video cards. The 64K window from D0000-DFFFF is often used by expanded memory managers, but LIM EMS can be disabled or the window can be moved to another location. Part of this range (D0000-DFFFF) is commonly used by Ethernet cards. Also, the E0000-EFFFF range is available on most PC clones, as well as IBM brand machines with memory management software that knows how to free up infrequently used portions of the IBM BIOS.

Table A-3 High DOS Memory Usage

Memory Range	Devices Commonly Assigned to This Range
A0000-A1FFF	VGA Video Memory	Blank	EGA Video Memory
A2000-A3FFF
A4000-A5FFF
A6000-A7FFF
A8000-A9FFF
AA000-ABFFF
AC000-ADFFF
AE000-AFFFF
B0000-B1FFF		MDA Video
B2000-B3FFF
B4000-B5FFF
B6000-B7FFF
B8000-B9FFF		CGA Video
BA000-BBFFF
BC000-BDFFF
BE000-BFFFF
C0000-C1FFF	16 bit VGA BIOS ROM	Same as below	16 bit EGA BIOS ROM
C2000-C3FFF
C4000-C5FFF
C6000-C7FFF
C8000-C9FFF	XT Floppy Controller	Part of this range is frequently used for shared RAM on an Ethernet card
CA000-CBFFF
CC000-CDFFF
CE000-CFFFF
D0000-D1FFF	Optional EMS Page Frame
D2000-D3FFF
D4000-D5FFF
D6000-D7FFF
D8000-D9FFF
DA000-DBFFF
DC000-DDFFF
DE000-DFFFF
E0000-E1FFF	IBM ROM BIOS
E2000-E3FFF
E4000-E5FFF
E6000-E7FFF
E8000-E9FFF
EA000-EBFFF
EC000-EDFFF
EE000-EFFFF
F0000-F1FFF		PC Clone ROM BIOS
F2000-F3FFF
F4000-F5FFF
F6000-F7FFF
F8000-F9FFF
FA000-FBFFF
FC000-FDFFF
FE000-FFFFF

Table A-4 PC Memory Usage

Memory Range Hexadecimal	Memeory Range Decimal	Commonly Assigned Device
00000-0FFFF	0- 63 KB	Conventional DOS Memory
10000-1FFFF	64-127 KB
20000-2FFFF	128-191 KB
30000-3FFFF	192-255 KB
40000-4FFFF	256-319 KB
50000-5FFFF	320-383 KB
60000-6FFFF	384-447 KB
70000-7FFFF	448-511 KB
80000-8AFFFF	512-575 KB
90000-9FFFF	576-639 KB
A0000-AFFFF	640K-703 KB	Upper Memory	Video RAM
B0000-BFFFF	704-767 KB
C0000-CFFFF	768-831 KB		VBIOS/Floppy
D0000-DFFFF	832-895 KB		EMS Page Frame
E0000-EFFFF	896 -959 KB		IBM BIOS
F0000-FFFFF	960-1023 KB		IBM/Clone BIOS
100000-10FFFFF	1024-1087 KB	Extended Memory (XMS)
110000-11FFFF	1088-1151 KB
120000-12FFFF	1152-1215 KB
130000-13FFFF	1216-1279 KB
140000-14FFFF	1280- 1343 KB
150000-15FFFF	1344-1407 KB
160000-16FFFF	1408-1471 KB
170000-17FFFF	1472-1535 KB
180000-18FFFF	1536-1599 KB
190000-19FFFF	1600-1663 KB
1A0000-1AFFFF	1664-1727 KB
1B0000-1BFFFF	1728-1791 KB
1C0000-1CFFFF	1792-1855 KB
1D0000-1DFFFF	1856-1919 KB
1E0000-1EFFFF	1920- 1983 KB
1F0000-1FFFFF	1984-2047 KB