SoundTraxx DSD-150/DSX Technical Reference User Manual

SoundTraxx Equipment

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This section of the manual is designed to provide the advanced user with additional insight into the operation and
capabilities of the SoundTraxx Digital Sound Decoder. By necessity, it is somewhat technical in nature and assumes
a working knowledge of the NMRA DCC Standards and RPs as well as a familiarity with binary and hexadecimal
number systems.

The novice user should not be dissuaded from studying this section as it will help add to his knowledge of DCC
technology and enable him to take greater advantage of its capabilities.

Copies of the NMRA DCC Standards and Recommended Practices may be obtained by contacting:

Technical Department
NMRA Headquarters
4121 Cromwell Road
Chattanooga, TN 37421 USA
Phone: (615) 892-2846

As always, our Technical Support staff will be happy to answer any specific questions you may have regarding the
SoundTraxx DSD.

Applicable Standards
The SoundTraxx DSD has been designed to meet the requirements of the following NMRA Standards and RPs as
defined by September, 1996:

Standard S-9.1

DCC Electrical Standard

Standard S-9.2

DCC Communication Standard


Electrical Interface and Wire Color Code


DCC Extended Packet Format


DCC Configuration Variable

RP-9.2.3 (Tentative)

DCC Service Mode


DCC Fail-Safe Operating Characteristics

Bit Timing
The DSD uses a quartz crystal timing reference and will recognize DCC packet bits that fall within the following
timing constraints:

“1” Bit, 52µS to 64µS
“0” Bit, 90µS to 12000µS

Packets containing bits that fall outside of this range will be rejected.

Addressing Modes
The DSD recognizes the following address modes and ranges as defined by RP-9.2.1:

Broadcast Address 00
Decoder Addresses 01-127
Consist Addresses 01-127
Extended Addresses 0xC000 - 0xE7FF

Packets contain addresses outside of these ranges will be ignored.

Command Instructions
The DSD will process valid packets containing the following instruction codes as defined by RP-9.2.1:

000 Decoder and Consist Control
All currently defined forms of this instruction are processed except 00000110b, Set Advanced Acknowledg-
ment. This instruction is ignored.

Digital Sound Decoder Technical Reference


This manual is related to the following products: