What is a UART?
A UART (Universal Asynchronous Receiver/Transmitter) chip is the heart of the modem. A UART chip takes the computers parallel data structure and converts it into a serial data stream. Older machines, such as an i486, often came with an 8250 or 16450 UART chip. These UART chips did not support the high speeds required by today’s communications standards. Today we use a 16550 UART for most modem communications. Some devices, like ISDN, can use ESP (enhanced serial port) chips for faster communications (up to several megabits of throughput).
