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.
  • If the block is empty nothing will happen.
  • Report as ghost train in all other cases.

Wrong Block

If a switch did not work, and a loco runs in an empty block in which the enter sensor is capable of identifying the loco, a swap destination will be triggered.

Following conditions must meet:

  1. The “second next block” option must be disabled.
  2. Blocks must have a separate enter and in events. (enter2in does not work.)
  3. A route must be exist to the 'wrong' block.
  4. The 'wrong' block may not be occupied.
  5. The enter sensor must be capable of recognising the loco Code.

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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