Apple Attachment Unit Interface ( AAUI ) is a mechanical re-design by Apple of the standard Attachment Unit Interface (AUI) used to connect computer equipment to Ethernet . The AUI was popular in the era before the dominance of 10BASE-T networking that started in the early 1990s; the AAUI was an attempt to make the connector much smaller and more user friendly, though the proprietary nature of the interface was also criticized.
30-399: AAUI is part of a system of Ethernet peripherals intended to make connecting over Ethernet easier. At the time of the introduction of AAUI, Ethernet systems usually were 10BASE2 , also known as thinnet. Apple's system is called FriendlyNet. A FriendlyNet 10BASE2 system does not use BNC T-connectors or separate 50 Ω terminators . Instead of a single BNC connector that is inserted into
60-469: A 10BASE2 BNC connector (that the T-connector plugs into), or it may offer an AUI connector that external transceivers (see Medium Attachment Unit ) can connect to. These can be transceivers for 10BASE2, but also for 10BASE5 or 10BASE-T. Some NICs offer both BNC and AUI connectors, or other combinations including BNC and 10BASE-T. With multiple connections, only one connector is designed to be used at
90-521: A T-connector placed inline, the FriendlyNet transceiver has two BNC connectors, one on each side, to which the cables are attached. The transceiver automatically terminates the network if a cable is missing from either side. Additionally, Apple 10BASE2 cables terminate the network when no device is attached to them. Thus the number of mistakes that could be made hooking up a thinnet network is reduced considerably. Since any of these mistakes can disable
120-419: A lack of standardization. 10BASE-T can be extended by making a new connection to a hub. A fault in a one hub connection does not necessarily compromise other connections to the hub. 10BASE2 systems did have a number of advantages over 10BASE-T. No hub is required as with 10BASE-T, so the hardware cost was minimal, and wiring was particularly easy since only a single wire run is needed, which could be sourced from
150-399: A maximum length of 500 meters (1,600 ft). Up to 100 nodes could be connected to a 10BASE5 segment. Transceiver nodes can be connected to cable segments with N connectors , or via a vampire tap , which allows new nodes to be added while existing connections are live. A vampire tap clamps onto the cable, a hole is drilled through the outer shielding, and a spike is forced to pierce
180-417: A maximum segment length of 185 m as opposed to the thicker RG-8 -like cable used in 10BASE5 networks with a maximum length of 500 m. The RG-58 type wire used by 10BASE2 was inexpensive, smaller and much more flexible than the specialized RG-8 variant. 10BASE2 can also use RG-59 cable. An Ethernet network interface controller (NIC) may include the 10BASE2 transceivers and thus directly provide
210-463: A sliding clip to mechanically secure the connection. AAUI replaces these with a small 14-position, 0.05-inch-spaced ribbon contact connector. This connector may have been chosen to avoid confusion with the monitor port on early Macintoshes , which also uses a DA-15. The connector locks into position using two clips or hooks on the sides of the connector outside of the shell which automatically clicks on when plugged in, and can be removed by pulling back on
240-566: A sliding sheath over the body of the connector, disengaging the hooks. Third-party AAUI devices often omit this sheath, requiring the user to directly squeeze small tabs on the sides of the plug housing to detach the hooks. AAUI signals have the same description, function, and electrical requirements as the Attachment Unit Interface (AUI) signals of the same name, as detailed in IEEE 802.3 -1990 CSMA/CD Standard, section 7, with
270-412: Is a stiff, 0.375-inch (9.5 mm) diameter cable with an impedance of 50 ohms , a solid center conductor, a foam insulating filler, a shielding braid, and an outer jacket. The outer jacket is often yellow-to-orange fluorinated ethylene propylene (for fire resistance) so it often is called "yellow cable", "orange hose", or sometimes humorously "frozen yellow garden hose". 10BASE5 coaxial cables had
300-413: Is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network . During the mid to late 1980s, this was the dominant 10 Mbit/s Ethernet standard. The use of twisted pair networks competed with 10BASE2's use of a single coaxial cable. In 1988, Ethernet over twisted pair was introduced, running at the same speed of 10 Mbit/s. In 1995,
330-402: Is derived from several characteristics of the physical medium. The 10 comes from the transmission speed of 10 Mbit/s . The BASE stands for baseband signaling, and the 2 for a maximum segment length approaching 200 m (the actual maximum length is 185 m). 10 Mbit/s Ethernet uses Manchester coding . A binary zero is indicated by a low-to-high transition in the middle of
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#1732773124396360-400: Is derived from several characteristics of the physical medium. The 10 refers to its transmission speed of 10 Mbit/s. The BASE is short for baseband signaling (as opposed to broadband ), and the 5 stands for the maximum segment length of 500 meters (1,600 ft). For its physical layer 10BASE5 uses cable similar to RG-8/U coaxial cable but with extra braided shielding. This
390-456: Is difficult to install and maintain. 10BASE5 was superseded by much cheaper and more convenient alternatives: first by 10BASE2 based on a thinner coaxial cable (1985), and then, once Ethernet over twisted pair was developed, by 10BASE-T (1990) and its successors 100BASE-TX and 1000BASE-T . In 2003, the IEEE 802.3 working group deprecated 10BASE5 for new installations. The name 10BASE5
420-401: Is limited to 30 with a minimum distance of 0.5 metres (20 in) between devices. In a 10BASE2 network, each stretch of cable is connected to the transceiver (which is usually built into the network adaptor) using a BNC T-connector , with one stretch connected to each female connector of the T. The T-connector must be plugged directly into the network adaptor with no cable in between. As
450-408: Is the case with most other high-speed buses , Ethernet segments have to be terminated with a resistor at each end. Each end of the cable has a 50 Ω resistor attached. Typically this resistor is built into a male BNC and attached to the last device on the bus. This is most commonly connected directly to the T-connector on a workstation. If termination is missing, or if there is a break in
480-678: The Fast Ethernet standard upgraded the speed to 100 Mbit/s, and no such speed improvement was ever made for thinnet. By 2001, prices for Fast Ethernet cards had fallen to under $ 50. By 2003, Wi-Fi networking equipment was widely available and affordable. Due to the immense demand for high-speed networking, the low cost of Category 5 cable , and the popularity of 802.11 wireless networks, both 10BASE2 and 10BASE5 have become increasingly obsolete , though devices still exist in some locations. As of 2011, IEEE 802.3 has deprecated this standard for new installations. The name 10BASE2
510-411: The bit period and a binary one is indicated by a high-to-low transition in the middle of the bit period. Manchester coding allows the clock to be recovered from the signal. However, the additional transitions associated with it double the signal bandwidth. 10BASE2 coax cables have a maximum length of 185 metres (607 ft). The maximum practical number of nodes that can be connected to a 10BASE2 segment
540-429: The cable has a 50 ohm resistor attached. Typically this resistor is built into a male N connector and attached to the cable's end just past the last device. With termination missing, or if there is a break in the cable, the signal on the bus will be reflected, rather than dissipated when it reaches the end. This reflected signal is indistinguishable from a collision and prevents communication. Adding new stations to
570-521: The cable, the AC signal on the bus is reflected, rather than dissipated, when it reaches the end. This reflected signal is indistinguishable from a collision, so no communication can take place. Some terminators have a metallic chain attached to them for grounding purposes. The cable should be grounded only at one end. Grounding the terminators at both may produce a ground loop and can cause network outages or data corruption when swells of electricity traverse
600-463: The coaxial cabling's outer shield. When wiring a 10BASE2 network, special care has to be taken to ensure that cables are properly connected to all T-connectors. Bad contacts or shorts are especially difficult to diagnose. A failure at any point of the network cabling tends to prevent all communications. For this reason, 10BASE2 networks can be difficult to maintain and were often replaced by 10BASE-T networks, which (provided category 5 cable or better
630-509: The cost of an external transceiver. Apple eventually abandoned the system and sold off the name. Macintosh Quadra , Centris , PowerBook 500 , Duo Dock II (for PowerBook Duo) and early Power Macintoshes have AAUI ports, which require external transceivers. By the time AAUI was nearing the end of its life, the cost of an AAUI transceiver became a burden for consumers. Later models include both AAUI and modular connector ports for directly connecting 10BASE-T; either can be used, but not both at
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#1732773124396660-418: The ends were not detachable, making it difficult to wire them through walls. Unfortunately, when mixing and matching Apple and non-Apple 10BASE2 devices, there were many seemingly natural configurations of cables and connectors which would cause the network to become unreliable or unusable in the area, reducing the value of the complex and proprietary Apple 10BASE2 wiring system. AUI uses a DA-15 connector and
690-692: The exception that most hosts provide only 5 volts of power rather than the 12 volts required for most AUI transceivers. An adapter containing a power supply to provide the required 12 volts was available from Apple to permit connection of standard AUI transceivers to an AAUI port. This facilitated direct connection to 10BASE-F ( fibre optic ) and 10BASE5 (ThickNet) Ethernet networks, for which AAUI transceivers were not available. [REDACTED] Media related to Apple Attachment Unit Interface at Wikimedia Commons 10BASE2 10BASE2 (also known as cheapernet , thin Ethernet , thinnet , and thinwire )
720-476: The nearest computer. These characteristics made 10BASE2 ideal for a small network of two or three machines, perhaps in a home where easily concealed wiring was an advantage. For a larger complex office network, the difficulties of tracing poor connections made it impractical. Unfortunately for 10BASE2, by the time multiple home computer networks became common, the format had already been practically superseded by 10BASE-T. 10BASE2 uses RG-58A/U cable or similar for
750-431: The network segment, this presents a significant improvement. FriendlyNet equipment was expensive. Because of this, Apple's computers, billed as having built-in Ethernet, were expensive to connect to Ethernet, perhaps adding as much as a tenth to the total price of the computer system. Additionally, AAUI held no advantage for any system other than 10BASE2, and thus as 10BASE-T became ubiquitous it became impossible to justify
780-400: The outer three layers and contact the inner conductor while other spikes bite into the outer braided shield. Care is required to keep the outer shield from touching the spike; installation kits include a "coring tool" to drill through the outer layers and a "braid pick" to clear stray pieces of the outer shield. Transceivers should be installed only at precise 2.5-meter intervals. This distance
810-476: The same time. 10BASE5 10BASE5 (also known as thick Ethernet or thicknet ) was the first commercially available variant of Ethernet . The technology was standardized in 1982 as IEEE 802.3 . 10BASE5 uses a thick and stiff coaxial cable up to 500 meters (1,600 ft) in length. Up to 100 stations can be connected to the cable using vampire taps and share a single collision domain with 10 Mbit/s of bandwidth shared among them. The system
840-759: The same time. AAUI connectors are also present on some Processor Direct Slot Ethernet adapter cards used in Macintosh LC and Performa machines. AAUI had disappeared by the late 1990s, when new Apple machines, starting with the beige Power Macintosh G3 series, include only the modular connector ports. Many third parties also created AAUI transceivers. Most made simplifications to the connectors and cables, presumably to reduce costs. Most third parties, as well as any non-Apple equipment, would use standard 10BASE2 cabling, including T-connectors and manual termination. Additionally, Apple's 10BASE2 cables were not appropriate for all uses since they only came in fixed lengths and
870-413: Was chosen to not correspond to the signal's wavelength; this ensures that the reflections from multiple taps are not in phase. These suitable points are marked on the cable with black bands. The cable is required to be one continuous run; T-connections are not allowed. As is the case with most other high-speed buses, segments must be terminated at each end. For coaxial-cable-based Ethernet, each end of
900-415: Was used) also provided a good upgrade path to 100BASE-TX . 10BASE2 networks cannot generally be extended without breaking service temporarily for existing users and the presence of many joints in the cable also makes them very vulnerable to accidental or malicious disruption. There were proprietary systems that claimed to avoid these problems (e.g. SaferTap) but these never became widespread, possibly due to
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