Complex sentence: The remote unit contains a mini test head which was capable of testing both of the lines between the RU and subscriber for faults, it would then communicate the results back to the EU digitally where mimics were presented to the normal exchange testing equipment.
Split into simpler sentences: The remote unit contains a mini test head that is capable of testing both lines between the RU and subscriber for faults. It then communicates the results back to the EU digitally, where mimics are presented to the normal exchange testing equipment.