If you are using your ATA as a replacement for your regular phone line, you may want to disconnect your home wiring from the Bell lines. This is much easier to accomplish if you have a "demarcation point jack" installed, such as the one above (disregard the thick white cable, it is unrelated). Disconnecting your line is as easy as unplugging the jack. This ensures that you will not broadcast your conversation on the Bell (i.e., incumbent) trunk; also, you will not be receiving any interference from possibly malfunctioning Bell equipment.