Data Acquisition Web

Using an existing interface saves the time and expense of designing something new. This is why the designers of the original IBM PC chose compatibility with the existing Centronics parallel interface and the RS-232 serial-port interface—to speed up the design process and enable users to connect to printers and modems already on the market. These interfaces proved serviceable for close to two decades. However, as computer power and the number of peripherals have increased, the older interfaces have become a bottleneck of slow communications, with limited options for expansion.

Nowadays the developers of a new standard form an organization to release it and handle development issues. Copyright of the USB 2.0 specification is assigned jointly to seven corporations, all heavily involved with PC hardware or software: Compaq, Hewlett-Packard, Intel, Lucent, Microsoft, NEC, and Philips. Companies have agreed to make specifications available without charge. The USB Implementers Forum's website has the latest versions of all USB specifications and other information useful for both developers and end users.

The ACCESS.bus sponsored by Philips and Digital Equipment Corporation, had many USB-like features. They made it available as an open standard. ACCESS.bus was in turn derived from the I2C synchronous serial bus. Although the electrical interface is different, many of the functions and features are a lot like what ended up in USB.