difference between narrowband and wideband audio codec

Hello,
In short - what is the difference between narrowband audio codec and wideband audio codec?
is it the narrownband audio codec has a sampling rate of 8Khz while wideband audio codec has a 16 Khz ?
or is it not always so ?
are there any other differrences ?
rgs,

mark

These references are usually used in radio transmission or other process like that. Where did you hear it?

Koz