Everybody is talking about the USB. In the long term, this new serial interface could replace many of the PC interfaces that have been used up to now. This is reason enough for looking at it more closely.Before getting into practical details, let’s first look at the basic features of the Universal Serial Bus. In USB Version 1.0, there are ‘lowspeed’ devices with a data rate of 1.5 Mb/s, and ‘fullspeed’ devices with a data rate of 12 Mb/s. Even the lower data transfer rate is several times faster than the possible baud rates of a serial interface.Up to now, we have often been faced with unpleasant situations in which all of the PC interfaces are already in use. The advantage of the USB here is that you can always make four new ports available by connecting a supplementary bus distributor (hub). Up to 127 devices in total can be connected to the bus.