The 8251 is a Universal Synchronous/Asynchronous Receiver/Transmitter (USART) packaged in a 28-pin DIP made by Intel. It is typically used for serial communication and was rated for 19.2 kilobits per second signalling rate.
It is commonly confused with the much more common 8250 UART that was made popular as the serial port in the IBM Personal Computer.
It includes 5 sections:
- read/write control logic
- transmitter
- receiver
- data bus system
- modem control