https://ncedcc.zendesk.com/hc/en-us/articles/200933425-Common-Cab-Questions 

• The NCE PowerCab / DCC Twin can only use cab bus addresses up to 10.
• 0-1 are the internal twin cabs.
• 2-7 are for throttles.
• 8-9-10 are for cab devices.
• The NCE AIU01 can use only cab bus address 4 or 48-63. That means effectively on a PowerCab bus it can only use address 4, there can't be more than one on the whole bus. Quite disappointing but OK enough for home since I had no plan to have more.

I got an NCE Switch-8 to learn what I can (and cannot) do with it for Randall.

Looking at the electronics on the board… If there’s one thing I like about the NCE electronics, it is that they are not fancy. This is the tech I grew up with and I can look at the board and recognize the components and understand what they do. I hope it will stay like that.

Microproc: PIC16F1936

http://www.microchip.com/wwwproducts/en/PIC16F1936

http://ww1.microchip.com/downloads/en/DeviceDoc/41364E.pdf

Pin 1 = Vpp (programing voltage)

Pin 8 = Vss (-)

Pin 20 = Vdd (+)

Power: MCC 7805CT

http://www.mccsemi.com/up_pdf/MC7805CT(TO-220).pdf

Front Left to Right : Pin 1 / 2 / 3

Pin 1 = Input / Left

Pin 2 = GND

Pin 3 = Output / Right

On the Switch-8, the large programming header can be used to get the +5 from the 7805.

From top, #2 is the +5 and #3 is the Gnd from 7805 (shared with the GND headers).

NCE AIU01: there's a similar 7805. A +5V can be soldered on the little through-hole just on top of the 7805 on the board. Measures 5V. For a single IR sensor, use a 220 Ω resistor.

From both the NCE USB v7 doc (see NCE website) or from

http://jmri.sourceforge.net/help/en/package/jmri/jmrix/nce/packetgen/NcePacketGenFrame.shtml

Example: 0xAD is for switching an Accy/Signal. There is no provision to read the state.

• E.g. 0xAD 0x00 0x03 0x03 0x00 ⇒ throw 0x0003 in normal direction
• E.g. 0xAD 0x00 0x03 0x04 0x00 ⇒ throw 0x0003 in reverse direction
• 0 is an invalid address.
• Max address is 2044 (0x7FC) which is a broadcast address for Accy.

Note: when trying in JMRI > NCE Command, "Binary" means hex without x, seriously \o/ ?

Lockout CV 556:

• Use on Address of input #1, which is 4 for my home one.
• 556 = 0x022C
• 0xAF is Ops ACCY programming.
• AF 00 04 02 2C [0=unlocked | 1=locked]
• This works. It locks buttons out.
• ACCY on controller can still be used to throw turnouts.

That means I can trivially command that from an Arduino and bypass JMRI if needed.

Experiment from tonight: control the EZTrack #6 crossovers using the NCE Q-Snap. ⇒ Failed.

I have 2 EZTrack #6 turnouts mounted in cross-over configuration. The idea was to power them from a single Q-Snap output to save one output for each cross-over.

The Q-Snap has no problem driving a single #6. But ever the largest timing I tried does not make the crossover (2 turnouts in parallel) toggle properly. They either bounce or switch half-way.

I also tried using a 9V DC power brick instead of the DCC power. That didn't help. Supposedly that way the turnout should get 9x2-2 = 16 VDC. However from experience I remember I always failed to trigger them in DC, which is why I previously used the AC from the EZTrack ACC power brick.

DigiX: 11 x 6 in

NCE Q-Snap: 4 x 3 in (DCC bus)

NCE AIU01: 4 x 3 (2 RJ12, comes with one cable)

XminiLab scope + board: 2 x 3 // 3.5 x 3 in

NCE UTP: 3 x 2 x 2 in deep

Notes:

• Q-Snap really needs 3 outputs per turnouts, it carries its own common per twin-coil. It's not clear whether I can share the commons since each one has its own capacitor.
• The DigiX relays OTOH work by sharing the AC common so I have 2 outputs per turnouts plus one common.

Yard Design 10 Rules: http://www.housatonicrr.com/yard_des.html very good intro.

        Somewhat unrelated, very interesting read on Housatonic Railroad Design Philosophy.

Tips of Freight Yard design: http://www.featherrivertrains.com/documents/kal_12248.pdf

Yard Operations and Design: https://www.x2011west.org/handouts/ldBootcamp-YardOps.pdf

Many LayoutVision pages relevant: http://www.layoutvision.com/id18.html 

        Love for the yard: http://www.layoutvision.com/id19.html 

        How to classification yard: http://www.layoutvision.com/id20.html

        Ops on a classic 4x8: http://www.layoutvision.com/id39.html

        Beware of CAD: http://www.layoutvision.com/id40.html (agreed on the S curves!)

Interesting design. Note that according to LayoutVison, typical west yards don't have an A/D.

Since I have IR reflective sensors, the idea would be to connect them to an NCE AIU01 to detect position in 2 or 3 spots for speed control and automation.

(Also I got an NCE Q-Snap to control 4 twin-coils, This would cover the front cross-over (2 turnouts), the yard entrance Y1 and the Y1/Y2 yard turnout. Really the point is learning and see what it’s good for since I can already control these turnouts with the Arduino/DigiX).

One idea is for speed matching, using one NCE AIU and 2 sensors.

• Embed the sensors in the EZTrack pointing up rather than side mounted.
• Use these directly using JMRI/jython.
• This leaves 12 unused inputs on the AIU.

This is my own understanding of the JMRI WiThrottle protocol based on reading the JMRI source code and connecting to a local JMRI server. I apologize in advance for the highly condensed notation style. I originally started looking into this to create my own python program; then back in 2014/2015 I used this  to create a Python extension of Scratch running on a Raspberry Pi to control JMRI. It was pointless yet it was absolutely cool and totally worth it. Eventually I used that same information to create my own Cab Engineer: DCC Throttle android app.

-- (start of info dump) --

JRMI WiThrottle protocol in action using [WiThrottle protocol doc].

Server code:

• DeviceServer.java for main codes (old sourceforge link: DeviceServer.java).
• ThrottleController.java for single throttle (T and S codes) (old sourceforge link: ThrottleController.java):

[2020 update: code now at https://github.com/JMRI/JMRI. Also note that all T/S throttle commands are now considered obsolete, using the MT multi-throttle commands is pretty much a given.]