G.723.1

G.723.1 is an audio codec for voice that compresses voice audio in 30 ms frames. An algorithmic look-ahead of 7.5 ms duration means that total algorithmic delay is 37.5 ms. Its official name is Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s. It is sometimes associated with a Truespeech trademark in coprocessors produced by DSP Group.[1]

This is a completely different codec from G.723.

There are two bit rates at which G.723.1 can operate:

6.3 kbit/s (using 24 byte frames) using a MPC-MLQ algorithm (MOS 3.9)\ 5.3 kbit/s (using 20 byte frames) using an ACELP algorithm (MOS 3.62)