Central IFB electronics station, gray. Contains all necessary control functions and electronics including line power, to provide the active link between the 4001, 4002 and 4003 control stations and the 4030 and IFB-325 user stations.
- Contains all necessary control functions and electronics including line power, to provide the active link between the 4001, 4002 and 4003 control stations and the 4030 and IFB-325 user stations