[Dhillon]

Could anyone plz explain the difference between a CODEC and a MODEM in terms of their functionalities....

[Apokalipse]

COder DECoder

basically, codecs are software used to decode video to be played, or encode video to be recorded.


MOdulator DEModulator

they convert (modulate) digital signals into analogue signals to be sent over a phone line.
they also convert (demodulate) the analogue signals back to digital signals that come from the phone line.
This is how modems communicate.

Although when you see a cable modem, or DSL/ADSL modem, they aren't really modem's. they only send and recieve digital signals. they don't convert from digital to analogue, or vice versa.

the name modem is used, basically for consistency.

a CODEC and a MODEM are really completely different things, although they do one similar thing: convert one thing to another, and back again.

[Dhillon]

thnx for the response buddy.. it is quite explanatory..

but i think even in case of DSL/ADSL or cable modems the transmission from the modem to the Service provider's switch is actually a high frequency carrier modulated by a bit stream of 0s ans 1s... e.g. the link connecting the DSL modem to DSLAM switch carries the signals which are inherently analog in nature and not the pure bits.

If this is true, then any MODEM we talk of, would always involve Digital to Analog conversion, and vice versa for the purpose of transmission.

Now some CODECS (like G.711 and G.729 etc.) are not only used for encoding-decoding the video to be played and stored, but also used in sth like a digital phone where analog voice is to be converted to digital bitstream again for the purpose of transmission.

This is what blurs the line of distinction between the two.. and is wat i want to have more clarity on..