Guy,
I would follow the link Mike provided to the NCE website. They have a very good chart listing which NCE decoders to use for various installation. As I recall from your previous post, you are a DCC newbie. While any manufacturer's decoders will work with any make DCC system, for you first few installs I would stick with NCE decoders. You undoubtedly will want to customize the decoders settings for things like lights or function mapping. With the PowerCab and a NCE decoder it is very simple to do through the menus on the PowerCab. The NCE decoder manual also walks you through not only the installation, but the programming of many of the aspects of the decoder. I feel that the Digitrax manual that comes with the decoder falls short in this area and will simply leave you wondering what to do next and having you coming back with more questions, not that there's anything wrong with that. One you get comfortable installing and programming decoders then branch out to other makes.
For example, the P2K GP-7 and GP-9 will both use a NCE P2K-SR. Atlas units usually use a DA-SR decoder.
Yes, I was at my LHS the other day, and the 1x3 series decoders from Digitrax are being phased out in favor of the 1x5 series. The 1x5's are equipped with sockets for Sound Bugs, so you will be getting a non-sound decoder with the ability to add a plug-in sound upgrade chip.
This is a nice option, particularly for those not ready for sound yet. You get the DCC capability now, but you don't have to start over with an expensive new decoder to switch to sound later. The Sound Bug is low priced, but it's just a sound unit, not a full decoder.
But....I'm going to suggest that you get a sound decoder for just one of your diesels before you make any other investments. There's a common experience here with those who get one sound engine, and then another, and so on. The sound engines are out there all the time, and the rest are gathering dust in the roundhouse. (I run my silent diesels in consists with sound engines, so they at least get running time. Yeah, and Jay and Silent Bob, my 2 non-sound geeps, drew track-cleaning duty the other day, too.) So, if you're like many of us, you'll quickly fall in love with sound engines, and you might decide to go all-sound from the start.
It takes an iron man to play with a toy iron horse.
I'd go to the decoder manufacturer's sites and see what they recommend. TCS even has some installation instructions and photos.
NCE - http://www.NCEDCC.com
Digitraxx -http://www.digitrax.com
TCS - http://www.TCSDCC.com
Mike
P.S. Sorry, I didn't remember how to make the addresses links.
Few weeks ago I posted a message about the choice between DC and DCC. Since then I opted for DCC and the NCE Powercab system. Now is time to think about puting decoders in my 10 loco. I want to begin with decoder without sound (except maybe for the 2-8-0). Can anyone help me choose the right decoder for each one of these :
Any advise will be welcome.
Guy
Modeling CNR in the 50's