Adaptive Multi-rate Wideband (AMR-WB): 7510 Media Gateway deals with media transmission and conversion from one medium to another, so it must support transcoding of multiple types. Uses a wider range of frequency for speech. This encodes the voice, for its transmission. You may see AMR-WB written as G722.2 as well.
A CODEC is what compresses and decompresses the voice during transmission.
Other media CODEC's that the 7510 supports are:
G.711: PCM, 64 kb/s
G.723.1: MP-MLQ, 6.3 kb/s
G.723.1: ACELP, 5.3 kb/s
G.726: ADPCM, 16/24/32/40 kb/s
G.728: low delay compression
G.729A/B: CS-ACELP, 8 kb/s