I’m not sure what this has to do with 1-800 numbers (are you calling a 1-800 number? do you have a 1-800 number)? You shouldn’t be getting telemarketing calls on your 1-800 number, as you’re paying per call.
Get an answering machine and screen your calls. I used to have the voicemail thing, but I replaced it with a machine, so I could hear who was calling, and decide wether to answer or not.
I also have this tone on my machine, at the beginning of the message (see attachment). A lot of auto-dialers will mark a number as unreachable or disconnected when they hear those tones.
Well if you think that is annoying. You should try having a fax machine call you at 4am every day for a week and see how annoyed you get… The solution. Hooked up the mac and turn on faxing to receive faxes. The next day i got the number that was faxing me and i sent them 150 messages that night saying STOP FAXING MY HOUSE… i think i wasted a lot of there paper but they got the ideas…
I had that happen too, scared the crap out of me the first time it happened. I wish I knew about hooking my computer up to the phone to receive the message, what an excellent way to get the message across.