Abstract: A group wiring patching device which has built-in light emitting device and filtering device coupled with wire pair receptacle thereof. When a testing voltage is applied to the circuit of the light emitting device, the light emitting device will emit light for assisting wire pair identification. The filtering device can minimize or even eliminate loop back shorting resulted by the circuit of the connected light emitting when communication signals or low voltage signals being applied thereto. Therefore, the group wiring patching device of the present invention will be able to perform ordinary signal transmitting functions without the need to remove the light emitting device after the wire pair identification process is done.

Abstract: LED lamp circuitry that emulates an incandescent lamp's behaviour upon remote verification of the LED lamp. The invention presents a fuse blow-out circuit and a cold filament detection circuit permitting the use of LED lamps in applications, such as railway signal light applications, where there is a need for remote monitoring of the lamps, while keeping the advantageous features of lower power consumption and longer life. The invention also provides a control circuit for enabling/disabling the power supply to LED lamps in relation to the level of the line voltage. The advantage of this embodiment is to avoid unwanted functioning of the LED lamp caused by interference from surrounding electrical cables.

Abstract: A system that utilizes a reference signal for testing signal paths for complex frequency response (linear distortion), and non-linear distortion. This reference signal, which is also known as a ghost canceling reference signal or a training waveform, has excellent properties for channel characterization. The reference signal is a waveform that operates for a major time interval that is subdivided into multiple minor time intervals. During each minor time interval, a sine wave oscillates at a constant angular velocity or frequency. The sine wave frequency may take uniform steps between the minor time intervals, or it may skip a group of frequencies. The phase of the waveform may optionally be continuous between the end of one minor time interval and the start of the next minor time interval. This waveform is generated by loading the time sample values from a digital memory into a digital to analog converter (D-A), or by rapidly reprogramming a numerically-controlled oscillator.