Instead of a number, all that shows on caller ID is UUU and for the number V320141002000183.  So far today have had 4 "Private Caller" calls going thru to voicemail and leaving no message and another call to my cell phone from 1-800- 312-2091, no name shown.   

You know what the V### stuff is, right?  The first digits are the date - 32014 = 3/20/14 and the next digits are likely the time of the call.  10:02 am perhaps?    I am not sure about the rest of the digits though.
I would guess the "UUU" stands for "DUUUH" for the nitwit who is calling you   .

Here is a forum thread on this topic:  http://800notes.com/forum/ta-3f0852449bac17d/caller-id-shows-v-a-whole-bunch-of-digits

Thanks for the note and the thread.  I didn't know what the V--- was before now.  I just keep seeing it and reporting, so now I know.  Today has been most frustrating, because after this note I received a couple more unidentified calls.  Busy, busy, busy!

we had one a while ago from V31404401700002

Love your cat!  Wish mine were a little more militant.  In response to your response I appreciate any insights in regard to garbage phone calls.  I found yef's info really interesting and now partially understand what the ID is about.  These calls sometimes get annoying and even scary.  It would be really interesting what the other digits indicate.