Thank you very much.
Mostly it depends on what the decoder supports. Most modern decoders support htem all - so they can still be used with older more limited systems. Direct Bit is the fastest, because in the absence of a full 2-way communication, basically the commadn station can ask the decoder somethign and the decoder can generate an ack or not. Since a given CV can have up to 256 values, in byte mode the command station essentially asks "is the value 0" "is the value 1" up util it gets an ack. That can be a LOT of queries. With Direct Bit you can read an entire CV in no more than 8 queries - "Is bit 0 = 1" "is bit 1=1" and form the value based on the acks received. Not a lot of commercial command stations do that. The SPROG is one that does, which is what makes it so fast - so long as the decoder supports it.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I am studying the DCC documentation, and contemplating the exercise of making my own command control device. I am reading through the "Service Mode" documentation, and there are a number of ways to edit CVs. I also know acknowledgements are necessary. There is a "Direct Write/Verify" method. There is a "Direct CV bit manipulation" method. I know some of this documentation is old and I can't tell what aspects are "old school" vs what aspects are "best practices" for building something practical today. Which of these methods are currently used by the latest technology? Could someone please give me a little explanation about why one might want to use one method over the other? Thanks.