Answer:
Step-by-step explanation:
modem is a hardware device stands for modulation/demodulation and is used to convert digital computer signals into analogue telephone signals and vice versa and allows computers to communicate over a transmission phone line.
whereas,
codec also is a hardware device or can be a software program stands for coder/decoder performs transmission on a data stream or signal and particularly is used in making multimedia files small enough to compact according to the desired requirements.