Abstract: The present invention teaches a bridging device for telephone communications which may be connected at customer premise locations in order to provide diagnostic information with respect to the line conditions of network side and customer side wiring. Visual indicators are electrically configured such that they may be selectively included in the circuit path between the network side and customer side wiring. The status of the visual indicators when the device of the present invention is placed in a test mode provides diagnostic information about the customer side and network side wiring, such as "short", "open" or "general trouble" indications. In one exemplary embodiment of the present invention two LEDs are used in combination within the bridging device. A first LED is attached in series with the wiring loop coupled to customer telephone equipment. A second LED is attached to a switch that shorts the wiring loop before the interface to the network wiring.