The older TN2302AP (Medpro), and the older G350/G700 media gateways will use 2 DSP resources when using a compressed codec, such as G.729, or G.723, while using a single resource for G.711MU/A
The newer TN2602 Media Processor, and the newer gateways, such as the G430/G450 use a single media resource for compressed and uncompressed codecs.
That is the simplest, clearest, explanation I can give you.
Mitch
AVAYA Certified Expert