Arrowvale Electronics has designed and manufactured a Drivers Interface Unit (DIU) that is remote from the Data Recorder, connected via RS232. This drivers' keypad includes a vandal-proof 12 button telephone-style keypad and a 20 character by 2 line liquid crystal back-lit display.

The interface can be programmed with over 100 Driver Identity Codes, to a range of lengths or forms, which can be entered by either the keypad or by the optional built-in TagIT and unique identity key.

A relay is provided which is switched when the correct drivers ID is entered and it has the facility to record other information such as train reporting number.

An OTMR Healthy Blue or Multicolour LED indicates that the recorder is functioning correctly.