Table of Contents

• Introduction
  
• NICs versus Transceivers
  
• Sample NIC Vendor and Cost Table
  
• Combo Connector NICs
  
• Transceiver Types for Network 21 Cutover
  
• Hints for Ordering NICs and Transceivers

Introduction

Switched 10BASE-T is the new campus standard for direct network connections and is the means by which data will be transmitted between the desktop and the campus network. The Network 21 project will install a state of the art, fiber optic backbone, seed campus communications closets with electronics to provide a switched 10BASE-T environment, and fund installation and modification of a total of 10,000 10BASE-T NAMs (Network Access Modules).

A network interface card, or NIC, is a printed circuit board or adapter that allows a computer to connect to a network. Network 21's 10BASE-T environment will require that every desktop computer or network device cutting over to the new Network 21 infrastructure be 10BASE-T ready. This means that NICs used to connect computers and network devices to Network 21 must also be 10BASE-T compatible.

A transceiver also can be used for this purpose by converting one type of ethernet connector to another or by converting one type of I/O port to an ethernet port. The transceiver can be plugged into a desktop computer or network device and then plugged into a 10BASE-T cable.

The purpose of this document is to act as a basic guide in considering the type of NIC or transceiver to purchase for the computers and network devices in your department. This is an overview only; for further information on purchasing hardware for transition to Network 21, see Client Hardware Recommendations for Network 21Cutover.

NICs versus Transceivers

A transceiver is recommended for:

• A Macintosh with an AAUI port (but no 10BASE-T connector);
• A slotless Macintosh (that does not accept an internal NIC);
• A Thinnet/BNC-only internal NIC that is impractical to replace (Note: a microrepeater would be used in this case rather than a transceiver.);
• An NCD X-terminal with a built-in AUI connector, but no 10BASE-T connector;
• Other network device with a built-in AUI connector, but no 10BASE-T connector.

A transceiver is not recommended for:

• A PC with an existing internal NIC that is not 10BASE-T capable (Purchase a new 10BASE-T NIC or a new combo connector NIC);
• A PC without a NIC (purchase a new 10BASE-T internal NIC).

When practical, it is preferable to replace an internal NIC than to use a transceiver. Consider the following:

• A transceiver attaches directly to the NIC and will require three to four inches of additional clearance between the NIC and the wall or other equipment.
• Some transceivers do not attach securely to the NIC and may be knocked loose.
• Some older NICs no longer perform adequately. It may be preferable to replace the card than to use a transceiver.

For the Macintosh, it is best to use the built-in AAUI port for your ethernet connection.

• If you have a recent model of a PowerMac with both an AAUI and a 10BASE-T connector, use the 10BASE-T connector.
• If your Macintosh does not have an AAUI port, you may be able to install an internal NIC. (Many Macintoshes have NuBus, Comm Slot or other expansion slots that can be used for an internal NIC.)
• If your Macintosh has neither an AAUI port nor an empty slot, you can use a SCSI to ethernet transceiver.
• If it is impractical to install a NIC in a NuBus slot, you can use a SCSI to ethernet transceiver.

Sample NIC Vendor and Cost Table

Important note: The specific cards and vendors listed in this table are only examples. It is at the department's discretion to select network interface cards, transceivers and/or vendors appropriate to its needs.

For an extensive list of vendors, you may want to browse The Ethernet Page compiled by the University of Texas.

Platform	Device	Manufacturer	Approx Cost
Various	AUI to 10BASE-T transceiver	Allied Telesyn	$ 30
PC	10BASE-T NIC	SMC, Intel, 3Com	$ 90-100
PC	10BASE-T/Thinnet/AUI combo NIC	SMC, Intel, 3Com	$110-130
Macintosh	Mac AAUI to 10BASE-T transceiver	Allied Telesyn, Farallon, Asante, Dayna	$ 40
Macintosh	10BASE-T NIC	Farallon, Asante, Dayna	$ 80-$115
Macintosh	10BASE-T/Thinnet/AUI combo NIC	Farallon, Asante, Dayna	$150-$175
Macintosh	SCSI ethernet adapter	Farallon, Asante	$300
Powerbook	AAUI to 10BASE-T transceiver	Farallon, Asante, Dayna	$ 40
Powerbook	SCSI ethernet adapter	Farallon, Asante	$240
LocalTalk only printers	Ethernet print transceiver	Farallon, Asante, Dayna	$240-300
HP & Laserwriter printers	JetDirect card JetDirect EX	Hewlett Packard	$200-$390

Note: The purchase of "rock bottom bargain basement" NICs is not recommended.

Combo Connector NICs

For more in-depth information regarding combo connector NICs, see Combo Cards: Network Interface Cards with Multiple Connectors.

A combo connector NIC is practical when the desktop computer or network device:

• Will be switched from Thinnet or Thicknet wiring to 10BASE-T wiring;
• Already has an internal ethernet NIC (e.g., PC ISA Bus, Mac NuBus, network printer, UNIX workstation);
• Is already connected to UCDNet;
• Does not yet use 10BASE-T (RJ45) connectors on its current NIC;
• Is not an acceptable candidate for a transceiver or fan-out device.

A combo connector NIC is not necessary when the desktop computer or network device:

• Is already using 10BASE-T LAN wiring (no change needed);
• Will not be joining a LAN until the Network 21 infrastructure is in place (In this case, purchase a plain 10BASE-T NIC);
• Is a Macintosh with an AAUI port, a slotless Macintosh or a Macintosh with a SCSI port.

Many NICs have more than one connector type on the card. Some cards have three types: Thinnet, AUI and 10BASE-T. If you have a combo connector NIC, you can continue to use your current connector type on UCDNet.

When purchasing a new NIC, look for one that automatically detects which connector is being used or that uses software for configuration. Avoid NICs that use hardware jumpers (which designate the connector to be monitored by the card). If your combo connector NIC uses hardware jumpers and you are not yet using 10BASE-T wiring, you will have to open the PC to move the jumpers at Network 21 cutover.

Transceiver Types for Network 21 Cutover

AAUI to 10BASE-T Ethernet (Macintosh):

The Apple Attachment Unit Interface (AAUI) ethernet adapter port is built in on newer Macs and Powerbooks. Use a transceiver to connect the AAUI port to your LAN wiring and an AAUI to 10BASE-T ethernet adapter to connect the AAUI port to the Network 21 infrastructure. [Note: Some recent models of PowerMac come with both an AAUI and a 10BASE-T connector. In this case, use the 10BASE-T connector instead of an AAUI transceiver. (You will need a 10BASE-T cable in either case.)]

AUI to 10BASE-T Ethernet (PC, UNIX, printers, Macintosh, etc.):

AUI to 10BASE-T transceivers are common and inexpensive. If it is impractical or impossible to replace the internal NIC in your device, you can use a transceiver to convert your AUI connector to a 10BASE-T connector. [Note: Some devices (e.g., Sun Sparc) require a slim-line model for proper connection.]

BNC to 10BASE-T Ethernet:

Thinnet to 10BASE-T microrepeaters are expensive. It is typically more cost effective to replace the NIC in your device than to use a Thinnet to 10BASE-T microrepeater. If you do decide to use a transceiver instead of purchasing a new NIC, use an AUI to 10BASE-T transceiver. [While it is conceivable that a microrepeater might connect an entire Thinnet segment (including multiple workstations) to a single 10BASE-T port, this is strongly discouraged under Network 21 policy. Please see the "10BASE-T Standard for Desktop Connections to Network 21" section of the "Network 21 Cutover Policy" document at http://tholianweb.ucdavis.edu/newcut.html]

SCSI to 10BASE-T Ethernet (Macintosh):

Powerbooks and some other Macs often come equipped with a built-in SCSI port. Use a SCSI to 10BASE-T ethernet transceiver on Powerbooks without an AAUI port. When it is impractical to install an internal NIC, use a SCSI to 10BASE-T ethernet transceiver for a Mac without an AAUI port.

Hints for Ordering New NICs and Transceivers

Consider the total cost of the NICs, transceivers and other equipment you are ordering. If the total amounts to $500 or less (including tax and freight), you may order through a department DOV, which is typically accomplished within a matter of weeks. If your order exceeds $500, however, it must be made through the Purchasing department and may take six weeks or more.

Check for volume purchase discounts. If you order five or more cards, for instance, you may qualify for vendor bundle specials.