Bi-Directional Communication




Pro's & Con's

Technique Pro's Con's Retrofittable PoM CV-read Available since
Barcode reader Yes No -
RFID Easy and inexpensive, except for the readers, to put transponders in all of the roling stock for tracking. Restricted² communication, ID only on enter.
Only usable fore small scale like N, larger scales will run to fast for the reader to detect.
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
After OpenDCC grounded and implemented BiDiB it became stable and usable. Need new DCC equipment. No Yes 2010(Tams)
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.

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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