A group of users can be created with a purpose of receiving voice announcements through the speaker of a telephone set, but it has to be in the waiting mode.
A device or a program, which is makes the transformation of data or
signal. Codecs can both code flow/signal (often for transfer, storage or
encoding) and decoding – for review or changes in the size, more suitable also
for these operations. Codecs are often used during the digital processing of
video and sound.