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I am constantly (5 or more times a day) getting calls where it rings once and then nothing. The caller's number does not show up in the caller ID on my phone, but if I am watching TV I will see the number displayed on the TV screen for a moment. Does anyone have an explanation for this?
It takes 2 rings tor the Caller ID information to appear on the Caller ID of your telephone. Apparently, only 1 ring for Caller ID on TV.
One ring is indicative of call-blocking software in your home; however, I'm sure you'd know if you had a call-blocker. Mouth is correct about "phone trollers." Companies can war-dial a block of numbers and whichever numbers connect (ring) would get added to a list. This company could use the data or sell it to other companies.