CBIs are mostly implemented in two parts; a section that implements the safety and failsafe requirements, and a second section that implements "non-vital" controls and indications.
Different manufacturers have their own brands of CBI such as
- SSI (Solid State Interlocking) - BR, Invensys, GEC-General Signal
- Mircrolok II
- Germany - Alister CBI from Funkwerk IT 
Interface between different brands
When interfacing different brands of CBI equipment, it may be necessary to use relays of each regime, which are then hardwired from one to the other. This happens in the middle of the Channel Tunnel where French and British signalling equipment meet.
Since only some of the major signalling organisations make CBI equipment, it was agreed that to prevent other players being left out in the cold, CBI equipment would be made available to those players at cost.
- Railway Gazette International of July 2012, page 18
|This rail-transport related article is a stub. You can help Wikipedia by expanding it.|