The RIT provides analogue interfaces for two additional radio transceivers, enabling the two-radio system to be expanded to support four or more radios. For data applications the RIT/D provides up to 64 kbps data transmission to and from the radio to any channel in the system.

The RIT has no user-adjustable controls. It can therefore be mounted in any convenient position and at any point in the highway 'ring', whether above or below a vehicle slip-ring.

Up to two RIT's can be added to a ROVIS installation to give a six radio capability.