Multiple downhole systems using multifrequency

A method for communicating between multiple sets of sensors along a single wire bus, comprising:

• injecting a legacy communication signal from a set of legacy sensors onto the single wire bus;
• injecting a first communication signal from a first set of tool sensors in a first communication zone onto the single wire bus;
• injecting a second communication signal from a second set of tool sensors in a second communication zone onto the single wire bus;
• receiving the legacy communication signal at a legacy receiving sensor of the set of legacy sensors from the single wire bus after the first communication signal and the second communication signal are filtered from the single wire bus;
• receiving the first communication signal at a first receiving tool sensor of the first set of tool sensors from the single wire bus after the legacy communication signal and the second communication signal are filtered from the single wire bus;
• and
• receiving the second communication signal at a second receiving tool sensor of the second set of tool sensors from the single wire bus after the legacy communication signal and the first communication signal are filtered from the single wire bus.