A very small number of my calls have a plus sign right before the phone number in the file name. For example: 1d20151130131758p+18001234567.flac
What does the plus sign mean?
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international version of your number, from the number +18001234567,
I am guessing you are from US.<br>
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None of the calls I've made have been international calls. They're not unusual numbers either. One of them is a local area code, and it's a number I've called and recorded dozens of times. Yet it only shows up with a plus sign one time.
Calls would not necessarily be international.
Some phones/operators add international sign for local calls too