I think it might be professional (mercenary) fundraisers who may be raising money for PBS or whoever else is willing to take money from them. I'd guess they probably keep most of what raise but not sure. I called them back and got a recording that identified them as something that sounded like "SDNA Quality Assuron" - couldn't really make it out - but the name wasn't PBS or HBO. The recording offered to take me off their list if I left my phone number in a voice mail. I chose not to do that though that might have been legitimate. Legit charity telemarketers have to give you the option to opt out.
I have received several calls from this number with a Caller ID as: PBS SOCAL. It is my belief that this is another fraud. It is a VOIP caller, and so many scammers use this computerized method of calling. There is an 800 number used by PBS Socal if one wants to make donations. Also, there is a 714 area code number for membership services, but the prefix is 241. The rule should be beware of solicitors who call us. We are all quite capable of researching any services we want. BEWARE!!!!!