Hot answers tagged

42

The performance (except for allowable cable length, see below) was the same between 10BASE5, 10BASE2 and 10BASE-T, and you have the complexity backwards: the coax is simpler than the twisted pair. The key point to remember is that Ethernet uses a shared transmission medium (much as radio does) that can carry only one message at any time. Thus, a transmission ...


25

I designed a 10BASET ethernet chip (codename ENZO used in Sage MainLAN https://archive.org/details/byte-magazine-1991-01-rescan/page/n67/mode/2up?q=sage+mainlan) and produced a proposed design for a 10BASET hub. In electronics terms 10BASET is simpler, a pair of resistors for pulse shaping the output externally, a transformer for isolation and for the input ...


20

Your question seems to ignore the topology of a network completely: If you want to connect, say 20 computers via Thickwire or BNC, you need: A length of the chosen cabling 20 MAUs if you want Thickwire Some cheap termination resistors That is: No active electronics except the MAUs (which you could consider part of the computer's Ethernet card) If you ...


19

Something that enabled functional multiaccess local area networks hardly seems like a mistake. At the time, or at least in my experience, your networked computers were in a dedicated room. The cables and vampire taps were awkward, true, but manageable in context. I actually had a fairly cynical view of 'cheapernet' (thinwire Ethernet), at least if it was ...


16

The per-port electronics in the network card is very similar, no matter whether you use 10base2 or 10baseT. AUI is slightly simpler on the network card, as a part of the electronics is not in the card, but in the MAU. The primary difference between coax and TP is that TP needs a hub or a switch, which is an additional electronic device and includes a second ...


10

Coax had the advantages of high bandwidth (twisted pair wiring at that time was only good for 1Mbps) and a simple collision distributed collision detection scheme for access control. The collision detection mechanism for 10Base5 involved detecting the DC level on the coax. When transmitting the attachment unit injected the manchester encoded signal with a ...


10

Following on from the answer from Jens, but with specific DEC information. I don't know about 'first', but the DELNI from DEC was a multiport Ethernet device for 'thickwire' installations. You could connect it to a standard cable, where it would provide access for 8 systems; use it standalone, for a small "ethernet in a box"; or cascade them for ...


9

As for the main question "what was the first Ethernet hub?", I cannot answer this, but my guess would be "multiple vendors came out with multiple hub models at the same time". See below for the reasoning. But I lived through the transition from a thick ethernet bus-topology to a tree-topology in the department of my university, so I can ...


4

Probably the slightly weird DELNI, which allowed multiple nodes to share one thickwire tap came out before but thinwire Ethernet (802.3a) and repeaters (802.3c) were both added to the Ethernet standard in 1985. DEC's classic 8 port thinwire + AUI DEMPR came out in 1986, and a cutdown 1 thinwire + 1 AUI version (DESPR) in 1987. The latter initially retailed ...


4

The other answers leave out a hub-like mechanism to attach 10BASE5. Often the thick yellow cable was an expensive asset, connecting one more vampire clamp wrongly could ruin it. The computers and the vampire clamp were connected by AUI cables, with 15 pin D-shell connectors, having a locking slider. So hubs were invented with multiple AUI ports, e.g. 8 ...


2

The first "hub" I saw was a multiport AUI connector. Probably less to save money, as they were expensive, too. But they reduced the risk of doing anything bad to the vampire clamps on the yellow cable (10BASE5).


1

Usually with information technology, the first version is simple and low-performance, and later versions are more complex, so the above is mildly unusual in that the first version was complex and high-performance. I think I would dispute that characterisation. The early versions of Ethernet used a coaxial cable with drop cables. That's pretty simple and ...


Only top voted, non community-wiki answers of a minimum length are eligible