What kind of data transmission is handled by the Physical Layer?

Question

Accepted Answer

Raw bit stream - The Physical Layer is the first and lowest layer of the OSI model. It is responsible for sending the actual raw bit stream from one device to another over a physical medium like a cable or wireless signal.

This means it takes digital data (0s and 1s) and turns it into electrical, optical, or radio signals that can travel through wires or the air. It does not understand addresses, encryption, or data structure — it only cares about moving bits physically.

This is helpful for interviews because:

You can confidently explain that the Physical Layer works only with raw data (bits)
You’ll know that things like IP addresses or encryption happen in higher layers, not here
You understand that this layer focuses on the hardware part of communication


Example: When you send an email, the Physical Layer is the part that sends the signals through the cable or Wi-Fi to deliver your message’s bits to the next device.

Conclusion: The Physical Layer handles raw bit streams, and it plays a key role in the actual transmission of data over the network.

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