X.75

X.75 is an International Telecommunication Union (ITU) (formerly CCITT) standard specifying the interface for interconnecting two X.25 networks. X.75 is almost identical to X.25. The significant difference is that while X.25 specifies the interface between a subscriber (Data Terminal Equipment (DTE)) and the network (Data Circuit-terminating Equipment (DCE)), X.75 specifies the interface between two networks (Signalling Terminal Equipment (STE)), and refers to these two STE as STE-X and STE-Y. This gives rise to some subtle differences in the protocol compared with X.25. For example, X.25 only allows network-generated reset and clearing causes to be passed from the network (DCE) to the subscriber (DTE), and not the other way around since the subscriber is not a network. However, at the interconnection of two X.25 networks, either network might reset or clear an X.25 call, so X.75 allows network-generated reset and clearing causes to be passed in either direction.

Although outside the scope of both X.25 and X.75 which define external interfaces to an X.25 network, X.75 can also be found as the protocol operating between switching nodes inside some X.25 networks.

Triumph X-75 Hurricane

The Triumph X-75 Hurricane was a 'factory special' motorcycle designed by fairing specialist Craig Vetter. The X-75 had swooping glassfibre bodywork, a three US-gallon petrol tank, lowered gearing and a distinctive triple exhaust on the right-hand side. The motorcycle is credited with creating a new class of motorcycle, the cruiser.

It was ultimately released as a Triumph model in 1973, the BSA factory having closed its doors in late 1972.

History

Vetter was commissioned by BSA's US distributor to customise the BSA Rocket 3 to appeal more to American tastes.

When, in 1968, the new BSA Rocket 3/Triumph Trident triples were shown to the American BSA-Triumph management, they were underwhelmed. They knew Honda had an important bike (the CB750) coming along, and they felt the triple's price of $1800 was too high and that technical details (like vertically-split crankcases and pushrod ohv valve train) were far from "cutting edge". However, they acknowledged that the bike was fast, and a sales team led by BSA Vice-President Don Brown decided to launch the bike by using a Rocket-3 to set some records at Daytona, records which were broken in 1971 by the Kawasaki Z1.