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Bi-Directional Communication



Technique Manufacturer Pro's Con's Retrofittable PoM CV-read
Barcode BarJut Yes No -
Arduino + GCA41
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
Transponding Digitrax Standard LocoNet, 'Listening' by wire. Mounting of transponding receivers need some special attention. Not very reliable. No Yes, tested
IR (Lissy) Uhlenbrock
Per's Model Train recognition system
Standard LocoNet, easy to install. Restricted communication, only info on 'eye contact'. Yes No
RailCom * After OpenDCC grounded and implemented BiDiB it became stable and usable. Need new DCC equipment. No Yes
Selectrix Müt Selectrix and address only. Yes No

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)

Reactions in Rocrail

Both tables show the reaction of Rocrail if a BiDi decoder is detected in a block.

Without create guest on BiDi

Mode Unknown Known Accept BiDi
Manual ignore set in block ignore
Automatic ghost ghost set in block

With create guest on BiDi

Mode Unknown Accept BiDi
Manual create guest + set in block create guest + set in block
Automatic ghost create guest + set in block

Channel 2 QoS

Channel 2 KMH

Channel 1 Direction

Channel 1 Address

Additional functionality

Automatic mode

  • Check the Code against the loco who reserved the block. If it does not match: Ghost.


Run manual loco into block

sensor-bi-directional-en.txt · Last modified: 2024/03/25 16:01 by rjversluis