In the past few months, we have received numerous suspected telemarketing calls from (spoofed?) telephone numbers matching the following patterns:
###-352-168#
###-352-169#

The specific numbers (and what showed up as their Caller IDs) are
209-352-1686  "WIRELESS CALLER"
310-352-1689  "OUT OF AREA"
323-352-1686  "OUT OF AREA"
323-352-1691  "OUT OF AREA"
341-352-1686  "CALIFORNIA"
415-352-1687  "OUT OF AREA"

We recognize none of these numbers, and find the similarity in phone numbers -- especially if you ignore the area codes -- to be very suspicious, as though the same person or group of people slightly varies their phone number to avoid being recognized as illegal telemarketers.

Fortunately for us, not one of these calls made it past our call-blocking device.