WTB2000 SYSTEM DESCRIPTION

Generally 

WTB is a backbone network for communication between vehicles in trains , redundancy is inherent.
WTB2000 is a basic building block of WTB communication nodes in trains.
WTB node is a communication part of a train control system stations or gateways.
There can be up 32 WTB nodes in a train.
WTB2000 encompasses physical and link layer of WTB protocol. For full node functionality the "Host processor" is required. The software library for OS-9 , VxWorks is available.
Options "Fritting" and "Sleep Mode" are on request. 

WTB2000 unit description

It is composed of 4 stacked boards with one VME connector.

• Processor board VTR360
• Medium Attachment Units (2pcs) A , B - MAU2TA, MAU2TB
• Sleep mode board VTR360S (power supply for the communication circuits of the unit)

There can be two - redundant communication lines called A - Main, B - Redundant.
Each node communicates in two directions - Direction1 and Direction2.
That means that each line in a vehicle is divided into two parts - sections A1, A2 respectively B1,B2.
There exist 4 communication sectors in a vehicle and 4 connectors A1, A2, B1, B2 on WTB2000 unit.

The node can be either in "End" or in "Intermediate" setting.
In the "End" setting sectors A1, A2 resp. B1,B2 are separated, both are terminated by passive terminators internally in MAU. This enables independent communication in different directions and adjacent vehicles can be detected and included in a composition.
In the "Intermediate" setting sectors A1, A2 respectively B1,B2 are connected by MAU relays that means that sectors create one common bus.

Initial state of train consists from all vehicles in "End" setting.
In so called "inauguration procedure" of a train one of the nodes configured as a "Master" sequentially detects other nodes and includes them in the composition. That means that nodes change their state from "End" to "Intermediate". 

Software