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HELP! Coax Cable Mapper Question ???

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New Member
Can someone explain how a Coax Cable Mapper works? In particular, what do the terminators do (and how do they do it) to the tone signal that allows the Unit to identify that particular terminator?


Well-Known Member
I don't know from any personal experience, but I reviewed some patents covering these devices and read some data sheets for products from different manufacturers. I believe that the terminator contains a resistor, and possibly a resistor in series with a diode. Each terminator would contain a different resistance and the possible range of resistor values is likely somewhere between 1K and 8K ohms. I note that the terminator cannot be anything fancy or the cost of the product would be higher than it is. The patent that I found covering a LAN cable mapper clearly indicates use of a resistor for identification. All the mappers place a maximum value of 100 or 200 ohms on the cable being measured, which leaves plenty of room to identify resistor values more than a few hundred ohms apart.

As far as i can see, these cable mappers (the kind that cost between $30 and $200) do not identify cable numbers using tones. In each case that I found, the tone function is an additional single output used for locating one cable at a time, not for indentifying multiple runs at one time.
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