BiDiB Data transmission

The BiDiB protocol can be used with various transmission media such as serial connection, USB, RS485, Ethernet (IP), a two-wire connection or wireless channel (with an adapted framing). Corresponding specifications can be found on the following pages.

Transport layers can be arbitrarily combined, the addressing method with the unique device identifier (Unique-ID) ensures correct message routing. The address coding theoretically allows to address 4261543936 different BiDiB devices.

The respective physical transmission layer ensures the correct framing and transparent byte transport of BiDiB message packets. Generally the transfer layer must secure the transport of the data with CRC.

The root endpoint of a tree segment (the interface) provides a list of all devices in its segment to the upper layer and manages logon and logoff of nodes within its segment.

Summary: netBiDiB

Packet-oriented network connection, built upon TCP/IP, especially suitable for connections of computers among each other. Automatic establishment of connections after one initial pairing.

Summary: BiDiB over Serial

Serial connection via RS232 or USB (virtual COM-Port), 3 possible speed settings (19200 Baud, 115200 Baud or 1MBaud), especially suitable for connections between computer and model railway layouts.

Summary: BiDiBus


BiDiBus is the model railway bus, which transmits BiDiB data within the model railway layout. BiDiBus is the easy to install and stable backbone of BiDiB within the model railway layout wiring.

It comes with the following advantages for the model railway enthusiast:

  • High speed
  • Secure transmission, insensitive to interference
  • Free wiring, easy configuration
  • Automatic notification of new nodes, no complex address allocation
  • Independent defective node failure detection
  • Large bus length, inexpensive cable
  • Open standard, future proof

BiDiBus key parameters

BiDiBus parameter (each segment)
Transmission technology: RS485
Speed: 500 kBaud
Wiring: Network cables (CAT5), max. 200m (656 feet), expandable via hubs
DCC-Bus: Integrated
Addressing: Automatic, no address allocation necessary
Hotplug: Connection and disconnection allowed during operation
number of subscribers: 32 at one level. over 1000 subscribers possible (via hubs).