NMRA Standards and Recommended Practices

This book is a reformatted one of the “Standards and Recommended Practices” of National Railway Model Association (NMRA).

Source repository https://github.com/kakkun61/nmra-ja/

Caution

This project is still in progress.

• S-9.1 Electrical Standards Done

To contributors

Please read Contributing.

• S-9.1 Electrical Standards
  • A: Technique for Encoding Bits
  • B: Command Control Signal Shape
  • C: Power Transmission and Voltage Limits for Transmitting Power through the Rails
• S-9.2 DCC Communications Standards
  • A: General Packet Format
  • B: Baseline Packets
  • C: Frequency Of Packet Transmission
• S-9.2.1 Extended Packet Formats For Digital Command Control
  • Format Definitions
  • A: Address Partitions
  • B: Broadcast Command for Multi-Function Digital Decoders
  • C: Instruction Packets for Multi Function Digital Decoders
  • D: Accessory Digital Decoder Packet Formats
  • E: Operations Mode Acknowledgment
  • Appendix A
• S-9.2.2 Configuration Variables For Digital Command Control
  • A: General Definitions
  • Appendix A: Manufacturer ID codes as assigned by the NMRA
  • Appendix B: Power Source Conversion codes as assigned by the NMRA
  • Appendix C: Process for changing Manufacturer Specific CVs to Optional or Uniform
• S-9.2.3 Service Mode Programming For Digital Command Control
  • A: Introduction
  • B: Service Mode Environment
  • C: Digital Decoder Entry to and Exit from Service Mode
  • D: Decoder Acknowledgment Mechanism
  • E: Service Mode Instruction Packets
  • F: Methods of Programming Required
  • Appendix A: Address Query Instruction
  • Appendix B: Service Mode Decoder Lock Instruction
• Contributing
• Glossary

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Original

The NMRA uses five types of Technical Documents to present information.

The NMRA, in its standards and recommended practices, addresses only the specific standards and recommended practices for model railroads. These standards and recommended practices do not address any legal requirements. It is the responsibility of the manufacturer to determine if their product conforms to all applicable governmental laws and regulations.

Standard (S)

NMRA Standards are to establish the broadest correlated set of limiting dimensions, electrical parameters and communications parameters within which interchange may be assured. Standards are reviewed by the membership and approved by the Board of Directors.

Recommended Practice (RP)

NMRA Recommended Practices do not rise to the level of being a Standard, however, they provide details of various topics that have been found to be the best for interchangeability or operation of products. Recommended Practices are not used in determining the qualification of a product when compliance certification is being judged. Comments are generally made if the product is found outside the recommended practice. Recommended Practices are reviewed by the membership and approved by the Board of Directors.

Technical Note (TN)

NMRA Technical Notes supplement the Standards to provide additional guidance on a given subject. Technical Notes are reviewed by the appropriate technical working group and approved by the Manager, Standards & Conformance.

Technical Information (TI)

NMRA Technical Information are documents that are used to provide information associated with a Standard or Recommended Practice. Technical Information is reviewed by the appropriate technical working group and approved by the Manager, Standards & Conformance.

Technical References (TR)

NMRA Technical References are, for the most part, internal documents that provide a history of action taken in the Standards and Conformance Department. Occasionally a Technical Reference is made public for reference and use by individuals involved with the Standards and Conformance Department. Technical References are reviewed by the appropriate technical working group and approved by the Manager, Standards & Conformance.

TODO