OK, I've been through every page of the DCC forum and can't find what I'm looking for. I have had an MRC Command 2000 DCC system and handheld controller for about the past 6 years and, while I love the system, I have just outgrown it. So I recently treated myself to a Digitrax Zephyr system with two UT-4 Throttles. All I can say is WOW. I run a lot of multiple consists and can't believe how easy it is on this system. The problem is much (like 60%) of my loco fleet uses older MRC AD310 decoders and the Digitrax system won't read the older decoders in order to program them (getting a "d nA" error). I can write an address in PAGED mode, and they seem to be programming (lights flash, motor hum) but when I put it on the main track - nothing. Is there a way to just write the CV's to the decoder without reading them? I'm still working my way through all the manuals, but am so far coming up with zilch. Or am I just doing something wrong? The AD310 decoders are 28 step decoders. I will convert my locos to digitrax if I have to, but at this point I'm looking at some serious bucks. That's a lot of decoders to buy at once. Your help would be greatly appreciated.