Hello, I would like to use the 2104 to monitor an compare analog phone lines, but ringer voltage is up to 80v. Any idea how to do that with the cheapest possible scope? Ognian
Then use x10 probes, what you may have to do is use the scope on a laptop without the power supply so that is floating to stop the ground of the PC interfering with the telephone lines.
Alternatively you can use a differential probe with the scope and that way you would not have to worry about grounding issues: