Filters, couplers, and repeaters
A wide variety of signal improvement and noise suppression equipment available. The devices in the table, many of which have both wired and plug-in versions, have these functions:
Noise Filter — A simple noise filter works along the lines of Figure 7, keeping power line noise from crossing the filter in either direction. You can use one to isolate a noise source from the rest of your system, or to isolate a malfunctioning device from high levels of noise on your overall system. Some noise filters allow signals at the X-10 120 kHz frequency through, but block nearby frequencies, while full-spectrum filters block frequencies above the power line 60 Hz.
Noise Block — A noise block is no different from a full-spectrum noise filter in principle, but it is packaged to make it convenient to install it right at the noisy equipment.
Signal Bridge — Also known as a passive phase coupler, a signal bridge transfers signals from one side of the electrical panel to the other. A passive coupler divides the available signal energy, lowering the signal on the sending side and increasing it on the receiving side.
Blocking Coupler — A blocking coupler, which is also a passive coupler, blocks entering X-10 signals as well as coupling signals between sides.
Phase Coupler / Repeater — You can boost the signal strength of the receiving side of your system with a phase coupler/repeater. The device actually receives and re-transmits the received signal, outputting it with far more strength than was received.
You have to be careful when installing filters to ensure that you don’t isolate X-10 transmitters or receivers from the network by blocking their signals. Noise blocks, for example, must be installed between the controlling receiver and the load, not on the power line side of the receiver.
It’s also important to avoid using multiple couplers or repeaters, because they’re not designed to work as multiples, and can either interfere with each other or (worse) echo signals endlessly until you disconnect one of them.