Probably a boiler-room telemarketing operation where immigrants are paid commission by "home improvement or solar power" contractors, or other telemarketing sales and services by the number of interested contacts they can rope in for sales or services. Often hang up when phone answered. Calling back their number .."not in service". I understand many of these contractors are out of state or "fly by night". When I have answered similar calls and had a live operator respond, he or she would hang up if I requested a company name, address, and callback number. I thought it was illegal under FTC regulations to make unsolicited phone calls from a number which did not receive incoming calls. Some of these calls are outsourced overseas as the "live operators" speak poor or broken English, even if they show a US area code. I have heard that "Vodaphone" can be tweaked by scam artists to show a US area code even if the call center is in India. Suggest readers on this forum should e-mail their congress person (Julia Brownley in Thousand Oaks) to try and put a stop to this nuisance.