Question

In asynchronous serial communication the physical layer provides ___________

(a) start and stop signalling

(b) flow control

(c) both start & stop signalling and flow control

(d) only start signalling

This question was addressed to me during an internship interview.

I need to ask this question from Physical Layer in section OSI Model of Computer Network

Answer 1

The correct option is (c) both start & stop signalling and flow control

The best explanation: In asynchronous serial communication, the communication is not synchronized by clock signal. Instead of a start and stop signaling and flow control method is followed. Unlike asynchronous serial communication, in synchronous serial communication a clock signal is used for communication, so the start and stop method is not really required.