They have a start bit and a stop bit so the receiving device can determine the start and finish. The sending and receiving device have to be synchronized before bits are transmitted. Higher speeds, but much more sophisticated and expensive equipment. Bandwidth is the range of frequencies that a transmission medium can carry in a given period of time. The higher the bandwidth, the more frequencies it can transmit.
Larger bandwidth means more data can be transmitted at one time.
In the last lecture I mentioned several communication channels such as phone lines, coaxial cable, and fiber optics. Now I want to discuss a few more that I didn't mention, but are relevant to this school. Dedicated lines are a connection that always is established between two communications devices, you can't call someone else, but you never get a busy signal. ISDN Lines - provides faster transmission rates than regular telephone lines. It's a technique that sends digital signals over an analog telephone line.