888-274-7677     
info@stevesdepot.com     
 
DCC Info
NMRA Standard CV Chart

Legend

  • Required:
    • M (Mandatory) - must be implemented in order to conform to the NMRA RP 9.2.2
    • R (Recommended) - strongly encouraged but not mandatory
    • O (Optional) - implemented at manufacturer's discretion
  • Default Value: the required factory default value when the CV is provided in an implementation
  • Read Only: indicates a CV whose value should be set by the manufacturer and which the user cannot modify
  • Uniform Spec:
    • Y - a CV which requires implementation by manufacturers according to a common specification
    • <blank> - the CV must be used for its designated purpose, but the action taken by the decoder for a specific value can vary between manufacturers
  • Dynamic: used for Unsolicited Decoder Initiated Transmission
CV Name CV # Req'd Default
Value
Read
Only
Uniform
Spec
Dynamic
(Volatile)
Additional Comments
Primary (Short) Address 1 M 3   Y    
Vstart 2 R          
Acceleration Rate 3 R          
Deceleration Rate 4 R          
Vhigh 5 O          
Vmid 6 O          
Manufacturer Version No. 7 M   Y     Manuacturer defined version info
Manufacturer ID 8 M   Y Y   Value assigned by NMRA
Total PWM Period 9 O          
EMF Feedback Cutout 10 O          
Packet Timeout Value 11 R          
Power Source Conversion 12 O     Y    
Alternate Mode Function Status F1-F8 13 O     Y    
Alternate Mode Function Status FL, F9-F12 14 O     Y    
Decoder Lock 15-16 O     Y    
Extended (Long) Address 17-18 O     Y    
Consist Address 19 O     Y    
  20           Reserved by NMRA for future use
Consist Addr Active for F1-F8 21 O     Y    
Consist Addr Active for FL, F9-F12 22 O     Y    
Acceleration Adjustment 23 O     Y    
Deceleration Adjustment 24 O     Y    
Speed Table/Mid-range Cab Speed Step 25 O     Y    
  26           Reserved by NMRA for future use
Decoder Automatic Stopping Configuration 27 O     Y   Under re-evaluation by NMRA
Bi-Directional Communication Configuration 28 O     Y   Under re-evaluation by NMRA
Configuration Data #1 29 1     Y    
Error Information 30 O     Y    
Index High Byte 31 O     Y   Primary index for CV257-512
Values 0-15 reserved by NMRA for future use
Index Low Byte 32 O     Y   Secondary index for CV257-512
Output Loc. FL(f), FL(r), F1-F12 33-46 O     Y    
Manufacturer Unique 47-64 O         Reserved for manufacturer use
Kick Start 65 O          
Forward Trim 66 O          
Speed Table 67-94 O          
Reverse Trim 95 O          
  96-104           Reserved by NMRA for future use
User Identifier #1 105 O         Reserved for customer use
User Identifier #2 106 O         Reserved for customer use
  107-111           Reserved by NMRA for future use
Manufacturer Unique 112-256 O         Reserved for manufacturer use
Indexed Area 257-512           Indexed area - see CVs 31 & 32
Index values of 0-4095 reserved by NMRA
  513-879           Reserved by NMRA for future use
  880-891         Y Reserved by NMRA for future use
Decoder Load 892 O     Y Y  
Dynamic Flags 893 O     Y Y  
Fuel/Coal 894 O     Y Y  
Water 895 O     Y Y  
SUSI Sound & Function Modules 896-1024 O     Y   See TN-9.2.3
           

1  If any of these features are provided, then this CV is Mandatory.


References

  • NMRA RP 9.2.2 (July 2007)