Econet is a networking system designed by Acorn Computers Ltd. It uses a
6854 ADLC (Advanced Data Link Controller) to implement a
serial network across a cable.
The cable consists of two twisted pairs. One pair for the
data signals, the other pair for the
clock signal. The final wire is an earth.
Econet is implemented (or capable of being implemented) in practically every computer Acorn has ever made, with the exception of the Electron, the A3010, the ill-fated Phoebe and the undetermined Peanut. Indeed, Econet support had been entirely removed from Phoebe, so it is likely that future Acorn-based machines will not support it unless a third-party method is provided. After all, the fastest I've pushed Econet to is a smidgen under 100K/sec. This would be a bit ridiculous on a computer that can manage a few tens of Mb/sec!
Econet saw it's glory in the mid eighties, where it was a simple and effective system for use in schools. A bog-standard E01S FileServer cost a little over £1000 (Acorn price index, 1990) and a 67Mb harddisc cost around £700 (advert in Acorn User, 1989). Instead of fitting discs and printers to each computer, you could buy a large disc and a good printer and a file server. Then all you need is to fit a network interface to each machine (about £75 for a BBC, or £50 for a Master/Arc Econet card). Much cheaper. Therefore, schools up and down the country that used Acorn computers used Econet. Econet, being robust, saw itself in businesses and factories, the "Cambridge Ring" and so and so.
It wasn't until SJ got in on the act that Econet saw serious serving. Indeed, the old SJ MDFS puts even Level 4 to shame. Offering a multitude of decent server facilities, and the SJ clock with its highly configurable clock pulses... SJ knew how to create servers, and that is why the MDFS is possibly the most highly regarded by Econet enthusiasts.