The Active Direct Inject box shall provide a transformer balanced and isolated feed from a source input via a 1/4″ TRS jack. The output of the DI box shall be via an XLR connector. The unit shall also provide a 1/4″ TRS jack in parallel with the input to act as a link for line bridging. The unit shall be self-powered via a main and standby battery system, or optionally through a phantom power source. An led shall indicate when battery power is low. Switches shall be provided for: PHASE REVERSE, EARTH LIFT (input/output), INPUT ATTENUATION of 0, 20 or 40dB), and the insertion of a LOW PASS FILTER, with roll-offs at 4kHz or 8kHz. The unit shall be housed in an isolated rugged ABS box to prevent accidental shorting when located on metal equipment.