Modulation and demodulation (as in modems) are part of which OSI layer?

Modulation is the process of converting digital data into analog signals for transmission, and demodulation is converting those signals back into digital data. These functions are handled by devices like modems and are part of the Physical Layer in the OSI model.

The Physical Layer is responsible for the actual transmission of data as electrical, light, or radio signals. Modulation and demodulation help the data travel over different types of physical media like telephone lines or radio waves.

Key points to remember:

• Modulation = digital to analog


• Demodulation = analog to digital


• Used by modems for internet over phone lines or wireless


• Handled at the Physical Layer (Layer 1)

Tip: If asked where modulation or the role of a modem fits in OSI, confidently say the Physical Layer — because its all about signal transmission.

Conclusion: Modulation and demodulation are part of the Physical Layer, helping data move over physical channels by converting signals for transmission and reception.