Which of the following processes can a transcoder perform?

A. conversion ofanalog audio to digital audio
B. conversion of digital audio to analog audio

C. conversion of digital audio from one codec to another

D. sampling, encoding, and compression of analog audio

Explanation:

A transcoder can convert digital audio from one codec to another. Transcoders enable communication between devices that support dissimilar audio codecs. For example, a transcoder can translate a G.729-encoded packet to a G.711encoded packet and vice versa. Transcoders translate the data stream inreal time between two devices so that no audio delay is experienced by either endpoint.

A digital signal processor (DSP), not a transcoder, can convert analog audio to digital audio and convert digital audio to analog audio. When analog audio is receivedby a DSP, the DSP samples and quantizes the analog audio data, encodes the data into binary format, and optionally, compresses it to conserve bandwidth. For example, Cisco Integrated Services Routers (ISRs) with DSP resources are used to process calls between Cisco Unified Communications Manager (UCM) and the public switched telephone network (PSTN).

Reference:
Cisco: Transcoders: Understanding Transcoders