KB531: MRC AD310 Mobile Decoder

This article was last updated on Aug. 20, 2011, 6:06 p.m. | Print Article | Leave Feedback

Q:  Using Digitrax systems to program an MRC AD310 decoder is especially confusing because the MRC Command 2000 uses several "switches" and "levers" rather than standard CV numbers. A conversion chart for the 10 possible MRC engine addresses would be a wonderful help to us old-timers.

A:  The documentation available from the manufacturer of this decoder is incomplete. Many older decoders such as this one are not able to recognize all the digital packets in use by more modern DCC Systems.

What we have learned is the MRC AD310 is:

  • Programmable up to 127 (1~127) locomotive addresses
  • Programmable for either 28 or 14 step operation modes
  • Has programmable start voltage
  • Has programmable acceleration rate
  • Has programmable deceleration rate
  • Offers directional lighting control for front and rear lights at 0.3 Amp rate


Operating a locomotive equipped with the AD310 mobile decoder with a Digitrax Zephyr Xtra or Zephyr:


In general, you should be able to select the AD310 with Zephyr or Zephyr Xtra and operate it successfully.

Programming the AD310 with Zephyr DCS50 or DCS51:


Be sure that you have the command station set to the correct programming mode.

MRC decoders can only be programmed in PHYSical mode.

Press the PROG key repeatedly until PHYS shows in the display.

The CV key will then cycle through the registers that can be programmed.

We believe that the AD310 decoder uses designations R1 through R8. Refer to the decoder documentation for which registers control which function.
We believe that R1 controls the locomotive address; input a value between 01 and 127 to assign this decoder a "short" address.

Do a status edit so the system knows that this locomotive address is either a 14 or 28 step decoder and not a 128 step one.

In many cases, Digitrax operators have been unable to select locomotives equipped with the AD310 because their system was set by default to address a 128 speed-step decoder.

You cannot reset this decoder by using CV08 set to a value of 08; the individual registers must be individually reset.

Because this article is somewhat vague, we welcome reader comments and clarifications, which will be incorporated into this document.

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