example, the Speedometer of a car measures the speed, changes in temperature in the body with a thermometer’s help, and weighs our body with a weighing machine.
ASCII—American Standard Code for Information Interchange
DCE stands for data circuit-terminating, data communications, or data carrier equipment - this is a modem or more generally, a line adapter.
DTE stands for data terminal equipment which generally is a terminal or a computer.
Basically, these two are the different ends of a serial line.