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DCC Working Group Discussion Topics

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Active Topics

Topics Forwarded to NMRA BOD and/or Membership for Approval

A discussion topic becomes "completed" when a conclusion to the discussion has been reached. This might be the adoption of a revised Standard or Recommended Practice, RP. This list includes those Standards that are currently awaiting approval by the NMRA members and RPs that are currently awaiting approval by the NMRA BOD.

Inactive Topics

A discussion topic can become "inactive" when interest wanes before some conclusion is reached. The NMRA DCC Working Group maintains them in this list of inactive topics so that historical information is still available if the topic is later revived.

Approved Topics

Approved Topics that have become Standards and Recommended Practices will normally be posted in the appropriate place on the NMRA web site. http://www.nmra.org/standards/sandrp/consist.html#standards-DCC, and other official documents of the NMRA. The short list of Topics below, were create by the DCCMWG for other purposes.

Topic 9910241 - Analog Output Instruction

Soundtraxx has proposed using a reserved packet format for analog output.

Work-in-progress drafts and background information will be posted periodically. (Updated July 9, 2004)

Brian Barnt is coordinating this topic.

Topic 0107122 - User Defaults

This became inactive in August of 2004. No prior information was available.

Topic 0104191 - CV Table Structure Proposal

This became inactive in August of 2004. No prior information was available.

Topic 0304231 - Additional Mfg CVs for Accessory Decoders

This topic has been inactivated and merged into Topic 0510241. (Updated March 31, 2006)

Topic 0305001 - Medium Plug Enhancement

Several manufacturers, including Roco and S-Helper Service, have been working on expanding the medium connector to support more functions. Several different options for standardization have been discussed.

Reinhard Mueller will try to coordinate discussion among the manufacturers. Work-in-progress drafts and background information will be posted periodically. (Updated July 27, 2004)

Closed July 2005 since it was superceded by Topic 0504023.

Topic 0305051 - Decoder Lock Proposal

The use of CVs 15 and 16 have been re-defined in RP-9.2.2 to accommodate this method and has been adopted by the NMRA BOD as implemented in RP-9.2.2. This topic is now considered closed. July 2007.

Topic 0307121 - New Decoder Register Matrix

This topic has been inactivated and merged into Topic 0510241. (Updated March 31, 2006)

Topic 0307161 - Clarification of sequence of Multiple Protocols

An additional comment was received about command stations and decoders supporting more than two protocols (i.e. DCC, Bi-Directional, Motorola), and what order that they should be in.

After discussion at the Summer 2004 and Fall 2004 Working Group meetings and on the Working Group mailing list, it was decided to move this topic to the inactive list on September 29, 2004. No drafts or background information had been created for this topic while it was active.

Topic 0307162 - Transition Sequence for Multiple Protocols

As a corollary to Topic 0307161, a comment was received about adding a possible transition sequence before changing to an alternative protocol in multi-protocol systems. An separate proposal was received to add a requirement in S-9.2 that all multi protocol operations end with the second half of a zero bit. This improves backward compatibility and resynchronizes the DCC signal.

Due to there being nobody actively working it, this was made an inactive topic in August of 2004.

Little historical information was available.

Topic 0307163 - Glossary

A proposal was received to convert the Draft Glossary document to a Technical Note.

Work-in-progress drafts and background information will be posted periodically. There is currently a glossary version there for comments. (July 21, 2004)

Topic 0307165 - Clarification / Rewording of RP-9.2.1 and RP-9.2.2

This topic refers to poor wording in a particular section of RP-9.2.1 and RP-9.2.2, and a possible conflict with the eventual RP-9.3.1 and RP-9.3.2. The wording must be made consistent with what was agreed to in the initial discussions.

Stan Ames is coordinating this topic. Work-in-progress drafts and background information will be posted periodically.

This topic on hold as of July 2004.

Topic 0309301 - RP-9.3.1 Revision

Extensive changes in the bidirectional communications have been proposed for RP-9.3.1. This includes changing the electrical specifications, baud rate, and timing of communications.

Peter Ziegler is coordinating this topic. Work-in-progress drafts and background information will be posted periodically.

Topic 0309302 - RP-9.3.2 Revision

In concert with the changes to RP-9.3.1 proposed in Topic 0309301, this topic proposes changes to the details of the messages communicated.

Peter Ziegler is coordinating this topic. Work-in-progress drafts and background information will be posted periodically.

Topic 0403131 - Working Group Organization and Operation

This topic was completed in December, 2004 with Working Group adoption of TN-2004-1 and its subsequent approval by the Technical Department Chair. The final documents, including a discussion of how the comments were addressed, can be found here.

Topic 0405221 - Streaming Mode Programming

The Working Group is discussing possible protocols for loading data into a decoder via a streaming-mode protocol. The goal is to allow loading large volumes of data to a decoder over the rails without having to remove the decoder from the engine. This can be useful in upgrading the decoder's firmware, loading sound data etc. This topic was created on May 22, 2004 after initial discussions within the Working Group.

Gil Fuchs is coordinating this topic. Development of a working prototype and associated documents for this topic is expected to take six months. Work-in-progress drafts and background information will be posted periodically.

On September 6, 2004, drafts of the protocol specification and background note were posted for comment.

Topic 0408251 - In-rush Current Compatibility

Modelers have reported incompatibilities between certain locomotives, decoders and command stations / boosters during the initial current draw. Related problems have been observed both in normal operation and when service mode programming. Members of the Working Group feel that this would be a good thing to coordinate among the manufacturers of locomotives, decoders, boosters, circuit breakers and others components. Discussions within the working group have started.

This topic was created on August 25, 2004 after initial discussions within the Working Group.

Mark Gurries is coordinating this topic.

Topic 0409061 - Asymmetric DCC signal

There are places on a model railroad where localized information needs to be transferred to a locomotive, e.g. e.g. to stop a train automatically at a certain place. This topic is an attempt to develop a common specification for doing via an asymmetric DCC signal. This is a signal where the positive-going part of the waveform has a different amplitude from the negative going part. A decoder can detect this difference and act on it.

This is intended to be an optional capability that can be implemented cheaply, and independently of the command station.

Reinhard Mueller will coordinate this topic. As there are already implementations on the market, with more expected, this topic should move quickly. This topic was crated on September 6, 2004.

Work-in-progress drafts and background information will be posted periodically. A draft has been posted.

Oct 2, 2005. This topic has become inactive until other topics, such as bi-directional, are completed.

Topic 0409121 - Improved Wiring of the Small Connector

This topic describes a recommended way of wiring the small connector so that lamps continue to work in DC mode in both directions. This wiring also provides a symmetric load.

The intention is to put this recommended wiring into an appendix of RP 9.1.1 so that manufacturers will know about it, and may use it or not without affecting the conformance of their product.

Reinhard Mueller will coordinate this topic. As this is a recommendation, not a requirement, this topic should move quickly. This topic was created on September 12, 2004.

A draft was posted on September 20, 2004.

Topic 0501151 - Additional Functions

Discussion is taking place on how to support additional functions (e.g. lights, sounds, etc) beyond the F0 through F12 defined now.

Reinhard Mueller will coordinate this topic.

This topic was officially closed April 2005 and replaced with Topics 0504021 and 0504022.

Topic 0504023 — 21-pin Connector

Reinhard Mueller is coordinating this topic. An addition to RP-9.1.1 has been written and has been forwarded to the NMRA BOD for review and approval at their January 2008 meeting. (see Topic 0603242). The suggested changes are posted here.

Topic 0504052 — Improper Use of NMRA Football

This topic has been closed and transferred to C&I for action.

Topic 0504054 — Use of NMRA Reserved CVs by Manufacturers

This topic has been closed and transferred to C&I for action.

Topic 0510241 - Additional Mfg CVs for Decoders

Dick Bronson, RR-Cirkits, is heading this effort to significantly increase the number of CVs for manufacturer use. This effort is for both Multi-Purpose and for Accessory Decoders. This is a merge of Topics 0104191, 0304231 and 0307121. See RP-9.2.2. RP-9.2.2 and RP-9.2.1 were approved by NMRA BOD January 2007.

Topic 0603241 — New Packet Format

Peter Ziegler is Topic Leader. The intention is to have the possibility of longer and faster packets.

Topic 0603242 — PluX Connector

Reinhard Mueller is coordinating this topic. An addition to RP-9.1.1 has been written and has been forwarded to the NMRA BOD for review and approval at their January 2008 meeting. The suggested changes are posted here.

Topic 0603243 — Scripts for Automated DCC Test Platform

This is now inactive due to PRICOM (Topic 0603245) dropping out of the Project.

Stan Ames is Topic Leader. Stan will coordinate the design of flow charts — starting with S-9.1 and S-9.2 — that will be used to write scripts that work in the PRICOM automated DCC Test Platform (See Topic 0603245). AJ Ireland will write the first flow chart of one test sequence to establish the format. Other manufacturers will be asked to complete the flow charts for other test swquences using the format established by AJ Ireland.

Topic 0603244 — Location Dependent Control

Peter Ziegler is Topic Leader. Peter will develop the protocol for Location Dependent Control. This includes defining what information is transferred and define what is to be done as a result of this information.

Topic 0603245 — PRICOM Automated DCC Test Platform Proposal

Didrik Voss is Topic Leader. A proposal from PRICOM has been enthusiastically accepted by the DCC Working Group. This topic deals with defining the criteria for the design and construction of this testing platform. Topic 0603243 deals with designing the testing scripts that will be used by this platform. The intent is to develop an automated testing platfrm for each manufacturer for use during development of new products. This will greatly speed up Conformance Testing and issuance of an NMRA Warrant of Conformance. Each manufacturer will participate in the cost of developing this platform and help to develop the scripts used by the platform.

Bob Scheffler, PRICOM, had to abandon this project due to personal reasons. We will be assigning a new topic leader to the topic in the near future. July 2007.

Topic 0706181 – Model Railroad Control Bus

This has been cancelled with the formation of a new WG called the NMRANet WG.

Topic 0707081 – MRRLCB – Control Bus

This has been cancelled with the formation of a new WG called the NMRANet WG.

Topic 0707082 – MR Accessory Bus

This has been cancelled with the formation of a new WG called the NMRANet WG.

Topic 0707091 – DCC Director

Brian Barnt, Topic Leader, will head this effort to better define radio control of decoders. July 2007.

Topic 0707092 – Large Scale Plug Pin Layout

Stan Ames, Topic Leader, is helping to define a large scale plug which will be adopted by all manufacturers. To date, each manufacturer has adopted a different scheme. July 2007.

Topic 0709211 – Suppression Circuits

David Nicholson, Topic Leader, will head a study of RF suppression circuits that will not interfere with the proper operation of DCC decoders.

Topic 0709212 – Phasing out 6-pin and 8-pin connectors

Reinhard Mueller, Topic Leader, is heading a study to phase out the 6-pin and 8-pin connectors for new models. The pins will always be defined in the RPs for legacy purposes.