How many times have been eating dinner or in the middle of a great TV show and the phone rings? Turns out it is a call from a telemarketing robo-dialer. This instructable will let them know your phone number should never be dialed again.
Back in the last century when phones went from rotary to tone dialing several things all happened at the same time. One of those was a thing called the Special Information Tone or SIT. This is a 1.1 second long tone that all dead or otherwise disconnected telephone lines was played upon contact. We have all heard it. it is the dee-dee dee tone.
Little known is the fact that when a telemarketer calls and hears this tone your number is moved from active to inactive database. There seems to be 3 or 4 data bases that serve all of the offenders. That means if you get 2 or 3 of them to move you to the bad number list they will not waste a call to a "dead" number.
i bought a 10 second greeting card recordable device on E-bay for less than $2.50. Coming from China it took a few weeks to get here but it was worth it. Get 2 as it is just fun to have one to play with.
I made a file with the SIT tones and proper duration on Audacity. i then pressed the red wire button on the device, and recorded the tone to the device. i held the microphone near my computer speaker. Pressed the yellow button when done to test the playback. satisfied i looked around for a box to put it in. i actually had a pill container the stuff fit in perfectly. See the second picture. i double sided taped the speaker to the top of the bottle and the yellow wired button to the side. I left the speaker and yellow wire switch drape over the threads for the top and snapped the top on. This screams Altoids box but i didn't want to deal with cutting metal.
I leave the device near the phone and when i see unknown number, no number or toll fre number on the caller ID, I simply pick up the device, press the yellow playback button and listen 2 seconds for hang up.
That's it. your number is now logged as a dead line. I did 3 times and have not gotten a call in 2 weeks. I have been on the Do not call list for 15 years and redo it every year but really gave my privacy back.
I will attach a file for you to record. I also will point to a vendor on Ebay that sells them cheap. there are dozens, pick your own.