Table of Contents

Bi-Directional Communication

Content → Objects → Sensors


www.digitrax.com_images_transponding.jpgwww.ringwelt.de_ejurat_barcodeerkennung_2ofinterleaved.jpgwww.merg.org.uk_merg_images_merg_logo.jpg


Standards

http://www.nmra.org/standards/DCC/

RailCom is according to the RP 9.3.1 and RP 9.3.2 of the NMRA.

The RailCom technology seems to be unknown/ignored in the USA. Transponding seems to be the well known bi-directional communication technology in the USA.

Any method of trying to send info back into the DCC supply is fraught with problems. RailCom is another example of this. (MERG)



Techniques


Pro's & Con's

Technique Pro's Con's Retrofittable PoM CV-read Available since
Barcode reader Yes No -
RFID Easy and inexpensive to put transponders in all of the roling stock for tracking. Restricted² communication, ID only on enter. Yes No -
Digitrax Transponding Standard LocoNet, 'Listening' by wire¹. Mounting of transponding receivers need some special attention. Not very reliable. No¹¹ Yes, tested 1997
LISSY Standard LocoNet, easy to install, open protocol. Restricted² communication, only info on enter. Yes No 2004
RailCom® NMRA RP 9.3.1??? Need new DCC equipment, additional PC-interface for reporting,
restricted per section, sections should be twice as long as the longest locomotive³. 		No Yes 2010(Tams)
2011(OpenDCC/BiDiB)
Selectrix/Müt Selectrix and address only. Yes No -


¹) Bundling detection sections is very flexible and 'unlimited'.
¹¹) None transponding decoders will cause unwanted events, so it is a DigiTrax only solution.
²) Data transfer is only possible at the “eye to eye” moment.
³) Some Railcars pickup current on both ends and could be in the need for more than one meter at H0 scale… See for more information the RailComDisplay page from Paco


PoM CV-Read

PoM = Programming on the Main, also referred as OPS (Operations Mode Programming).

  • Very fast, no polling but direct answer.
  • If only interested in CV-Read, only one transponder receiver is needed for the whole layout. (Transponding)


Manual Mode

  • Show ident code, or loco ID if a match is found in the table, in the clients.
  • Set block as reserved in case it matches a loco.


Auto Mode

  • Check the ident code against the loco who reserved the block.
  • Set block as reserved (with the restrictions below) in case the ident code matches a defined loco and the block allows half auto mode.
  • The matching loco to the reported ident code will replace the occupying loco when the ident is different.
  • If the block is empty nothing will happen.
  • Report as ghost train in all other cases.

Accept Ident

If the block state is set to “Accept Ident” and it is not reserved or occupied:

  • The block symbol will show green until an ident code is reported.
  • The block cannot be reserved by automatically running locos in this state.

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