RE: Futaba FASST 6
Gary,
As I mentioned in the other Futaba thread, its a by product of advancing IC technology. Power dissapation in an IC is a function of the supply voltage squared times the operating frequency of the internal digital logic (and a copule of other factors). As chips get faster, you have to reduce the supply voltage in order to keep the power (and thus the heat being dissipated) in the IC down. Its likely that the internal supply voltage on the processors we both used to post these messages is 1.8V or less - specifically to keep the power dissipation (heat) down. On a chip as big and expensive as a processor, you can affort to put on the extra resources to bump the I/O signal voltages up to normal PCB voltages (actually 3.3V or less themselves now a days), but on something like an RC receiver/decoder chip, you can't afford to do that.
As I've said before, Futaba has effectively issued a new standard for signaling voltages in RC applications and I never really thought that they would change it. As a 3rd party vendor, HiTech wil likely make any necessary changes to insure that their servos work OK with this lower signal voltage fairly quickly (although I personally wonder why anybody flys those things - see above, YMMV). You will likely see JR/Spektrum stuff operating at these new voltages sometime in the future as well as they move to newer IC fabrication technologies - especially if they are coming out with a generation 2 system that uses FHSS instead of the current "Rube Goldberg" approach...
Bob