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29-413: The industry's first third-party SBus cards were announced in 1989 by Antares Microsystems; these were a 10BASE2 Ethernet controller, a SCSI-SNS host adapter, a parallel port, and an 8-channel serial controller. The specification was published by Edward H. Frank and James D. Lyle. A technical guide to the bus was published in 1992 in book form by Lyle, who founded Troubador Technologies. Sun also published

58-512: 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 the cable, the AC signal on the bus is reflected, rather than dissipated, when it reaches

87-409: 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

116-406: 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 is the case with most other high-speed buses , Ethernet segments have to be terminated with

145-413: 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

174-439: A data rate of 10, 100, or even 1000 Mbit/s. They can provide for driving up to 500m of coaxial trunk cable without the use of a repeater . Additionally, a MAU: In addition to receiving and transmitting network data, MAUs perform jabber detection, in which they remove from the network any node that continuously transmits for longer than the maximum-length packet. This is done to prevent network disruption. Jabbering indicates

203-453: 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 is limited to 30 with a minimum distance of 0.5 metres (20 in) between devices. In

232-419: 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

261-417: 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

290-407: A possible problem with the node's NIC . MAUs also help troubleshoot problems with signal quality and integrity. They can test for signal quality errors, which can detect silent failures in the circuitry, as well as perform link integrity functions, which can detect breaks in wire pairs. Both these tests assist in fault isolation. Collision detection and loop-back functions direct transfer through

319-550: A separate adapter and was generally integrated into the NIC. Eventually, the entire Ethernet controller was often integrated into a single integrated circuit (chip) to reduce cost. In most modern switched or hubbed Ethernet over twisted pair systems, neither the MAU nor the AUI interfaces exist (apart, perhaps as notional entities for the purposes of thinking about layering the interface), and

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348-656: A set of books as a "developer's kit" to encourage third-party products. At the peak of the market over 250 manufacturers were listed in the SBus Product Directory, which was renamed to the SPARC Product Directory in 1996. SBus is in many ways a "clean" design. It was targeted only to be used with SPARC processors, so most cross-platform issues were not a consideration. SBus is based on a big-endian 32-bit address and data bus, can run at speeds ranging from 16.67 MHz to 25 MHz, and

377-479: A year some Sun systems used MBus , another interconnection standard, as a CPU—memory bus. The SBus served as an input/output bus for the rest of its lifetime. 10BASE2 10BASE2 (also known as cheapernet , thin Ethernet , thinnet , and thinwire ) 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

406-450: Is capable of transferring up to 100 MB/s. Devices are each mapped onto a 28-bit address space (256 MB). Only eight masters are supported, although there can be an unlimited number of slaves. When the 64-bit UltraSPARC was introduced, SBus was modified to support extended transfers of a 64 bits doubleword per cycle to produce a 200 MB/s 64-bit bus. This variant of the SBus architecture used

435-429: Is that the AUI deals with line-coded signals, which is specific to the physical medium (10BASE5, 10BASE2 and 10BASE-T all use the same line code), while MII is genuinely media-independent. So while MII and AUI as external connections were similar from a user's point of view, in terms of signalling the equivalent of MII for classic Ethernet were the non-standardized interfaces between MAC and Serial Interface as found in e.g.

464-619: The Am7990 family. The purpose of a MAU is to provide the physical means for communication between local network data link entities. As a physical interface, an MAU can be implemented independently among different hardware manufacturers and achieve the intended level of compatibility when interconnected in a common local network. It also allows for ease of installation and service. MAUs provide an easily accessible communication channel capable of high bandwidth and low bit error ratio performance, at relatively low cost. MAUs support message traffic at

493-525: The SPARCstation 1 . The design also allows for double- or triple-width cards that take up two or three slots, as well as double-height (two 3x5 inch boards mounted in a "sandwich" configuration) cards. SBus was originally announced as both a system bus and a peripheral interconnect that allowed input and output devices relatively low latency access to memory. However, soon memory and central processing unit (CPU) speeds outpaced I/O performance. Within

522-688: The category 5 (CAT5) (or better) cable connects directly into an Ethernet socket on the host or router. For backward compatibility with equipment that still had external AUI interfaces only, adapter-type MAUs with 10BASE2 or 10BASE-T connectors long remained available after the obsolescence of original vampire tap MAUs, but even adapter-type MAUs have become very rare as of the 2020s. The original Ethernet's successor standard, Fast Ethernet , introduced division into medium access control (MAC) and physical ( PHY ) layers connected with media-independent interface (MII). Some early Fast Ethernet hardware had physical external MII connectors, functionally similar to

551-508: The AUI connector, but generally separate adaptors became obsolete. However, the tradition of using a separate low-level I/O device in networking has continued in fast optical fiber network interfaces, where the GBIC , XENPAK , XFP , and enhanced small form-factor pluggable (SFP+) pluggable transceiver modules using the XAUI interface play a similar role. The main difference between AUI and MII

580-450: The MAU. In normal mode , the MAU functions as a direct connection between the baseband medium and the data terminal equipment (DTE), enabling message traffic between stations. Data output from the DTE is output to the coaxial trunk medium and all data on the coaxial trunk medium is input to the DTE. In monitor mode or isolated mode , the MAU functions as a receive-only connection between

609-432: 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 the coaxial cabling's outer shield. When wiring

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638-476: 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

667-407: 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 the bit period and a binary one is indicated by

696-418: The same form factor and was backward-compatible with existing devices, as extended transfers are an optional feature. SBus cards had a very compact form factor for the time. A single-width card was 83.82 millimetres (3.300 in) wide by 146.7 millimetres (5.78 in) long and is designed to be mounted parallel to the motherboard. This allowed for three expansion slots in the slim " pizza box " enclosure of

725-409: The same time. Medium Attachment Unit A Medium Attachment Unit ( MAU ) is a transceiver which converts signals on an Ethernet cable to and from Attachment Unit Interface (AUI) signals. On original 10BASE5 (thicknet) Ethernet equipment, the MAU was typically clamped to the Ethernet wire via a vampire tap and connected by a multi-wire cable to the computer via a DA-15 port, which

754-414: Was also present on the network interface controller (NIC). This AUI cable could be up to 50 metres (160 ft) long, but was typically much shorter. With later standards, thicknet vampire taps and N connectors gave way to BNC connectors (for thinnet coax cables ) and 8P8C connectors (for twisted-pair cables ). MAUs for these were still connected to NICs via AUI cables, but soon the MAU ceased to be

783-544: 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, 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

812-415: 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

841-432: 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 is derived from several characteristics of

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