Its an older servo, and tech info is hard to find - Airtronics site is just pathetic as far as info is concerned even for current products, much less legacy products.
I was told this was digital by several guys and Google turned up a several sales on various forums (RCTech, RC Universe, RC GRoups) where it was advertised as digital. I searched some more this am and see that the 94357Z is listed as an analog servo in other places where tech data is available. If the one in question is the same as the "Z" servo, then it looks like this is really analog an not digital. My bad, sorry about any confusion.
I still wouldn't swap it for a traxxas digital cheapie thats way slower.