3600 which is an exclusive Motorola trunking format which can carry analog and digital (Motorola ASTRO Digital) and hence it is not a standard that many other MFG use without paying licensing fees to Motorola.
This is why you only see a few other MFG supplying 3600 smartzone or smartnet systems, these other Mfg's pay Motorola to include these trunking formats in their radios.
Think of it like EF Johnson's LTR trunking, GE/Ericsson/macom/Harris has their proprietary EDACS trunking, and Motorola has their proprietary smartnet and smartzone which is the 3600 baud format.
9600 baud trunking is actually a Di-bit 4800 baud system, hence the 9600 reference.
It is the Apco P25 trunking standard but to call it an open standard is not really true because the codec still needs to be licensed to DVSI and the fees are ridiculous.
Mike