[1] It is a partial implementation of Siren 7 audio coding format (which offers bit rates 16, 24, 32 kbit/s) developed by PictureTel Corp. (now Polycom, Inc.).

[2][3] Its official name is Low-complexity coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss.

It uses a modified discrete cosine transform (MDCT) audio data compression algorithm.

As ITU-T Recommendation G.722.1, it was approved on September 30, 1999 after a four-year selection process involving extensive testing.

The computational complexity is quite low (5.5 floating-point MIPS) for an efficient high-quality compressor, and the algorithmic delay end-to-end is 40 ms.