<a href="http://en.wikipedia.org/wiki/555_%28telephone_number%29" rel="nofollow">http://en.wikipedia.org/wiki/555_%28telephone_number%29</a><p>Much more interesting (from a hacker's perspective) were all the telco services provided using specific exchanges. For any given ILEC there was an exchange used for services provided to customers or employees, including everything from phone testing services and remote terminal access to business customer information and voicemail. By calling these numbers you could find some neat hidden services, and they were free from any phone. You can imagine how bored kids at school with a payphone could discover quite a bit in their spare time.<p>The DATU was my favorite. It was a secret lineman's number to test circuits, which also enabled you to listen in on live lines. Using these numbers without proper authorization meant jail time, but they had to catch you first :) Ringback was also a fun way to pass the time. Dial the number and hang up, and 30 seconds later the phone would start ringing, and i'd watch who would go answer it. Like I said, bored kids...
I have the phone number 5555 5555 in a capital city - it's unlisted, never advertised, and still gets about 10 calls a day, mostly from babies and drunks. If you do get a number like this, and want to use it, I would suggest putting it behind an IVR and asking callers to press * to continue. We dump all the non compliant users to a voicemail, which is entertaining to listen to once in a while.<p>When we got the number first, it was not possible to call it from the major mobile networks as they had blacklisted it as a test number!
Not only are they not fake, but you can have one today!<p>Callcentric is an "internet phone service", which has been around for at least 8+ years. They allow you to search for unused phone numbers [1] in various area codes [2]. I searched for unused 555 numbers in the following area codes (213, 310, 626, 818) all have some available! So, you could create an account, and for something like $3/month, forward this 555 number to your existing number [3].<p>[1] <a href="http://www.callcentric.com/did_lookup.php?type=check_by_us_number&prod_id=7&npa=213&nxx=555&sub_did.x=37&sub_did.y=8" rel="nofollow">http://www.callcentric.com/did_lookup.php?type=check_by_us_n...</a><p>[2] <a href="http://www.bennetyee.org/ucsd-pages/area.html" rel="nofollow">http://www.bennetyee.org/ucsd-pages/area.html</a><p>[3] <a href="http://www.callcentric.com/dids/phone_number_sale" rel="nofollow">http://www.callcentric.com/dids/phone_number_sale</a>
This isn't new at all. For as far back as I can remember you could dial 555-1212 from any area code and get directory assistance for that area code. There's even a toll free 800 number (1-800-555-1212) which prompts you for the city you'd like.<p>Haven't used it in a long time (<i>seriously who would when you can search the internet on your smartphone?</i>) but I think it's the same service as 411 minus the $X/min fee (the 800 number version is free, I think the non-800 versions might bill you).
UK numbers for drama...<p><a href="http://stakeholders.ofcom.org.uk/telecoms/numbering/guidance-tele-no/numbers-for-drama" rel="nofollow">http://stakeholders.ofcom.org.uk/telecoms/numbering/guidance...</a>
Slight correction needed to the article: Mexico left the NANP in the late 90s and has adopted its own country code and dialing plan. It hasn't changed much since but you do need to use 011 and whatever code it is now to dial there.