G.723
G.723 is an ITU-T standard speech codec using extensions of G.721 providing voice quality covering 300 Hz to 3400 Hz using Adaptive [Differential Pulse Code Modulation] to 24 and 40 kbit/s for Digital [Circuit Multiplication Equipment|digital circuit multiplication equipment] applications. The standard G.723 is obsolete and has been superseded by G.726.
Note that this is a completely different codec from G.723.1.