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Maintaining / Phreaking modems lines using ANAC numbers

© September 2003 Dirk Hart
Web Site: MailStarUSA.com

I walked into a pile of modems today. Although acessing servers using modems is more secure than telnet they are still holdovers from yesteryear. Nonetheless, my client had one modem for outbound FAX from the server, two more for inbound connections, and one for an unused outbound connection. Somehow, as the years drifted by, we lost track of which modems were for inbound connections and which were outbound. The wires went to jacks on the wall, but these were unmarked. How was I to know what the telephone number was that connected to each modem?

I remembered that I talked to one lineman who had a number he called and an electronic voice would repeat back the telephone number that he had called from. After twenty minutes of googling I found that what I wanted was called an ANAC (Automatic Number Announcement Circuit) number. After a bit more googling I found ttp://text.staticfree.info/anac.txt . The ANAC numbers are also given in https://www.cs.uu.nl/wais/html/na-dir/alt-2600/faq/.html , a very rich collection of information.

I started dialing and soon had the whole mess documented.

Copyright September 2003 Dirk Hart All rights reserved

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-> Maintaining / Phreaking modems lines using ANAC numbers


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More Articles by © Dirk Hart

That's great info, Dirk! I use this number, preprogrammed into a Harris headset I keep in my toolbox. It has not let me down yet:


- Bruce Garlock

815 200-3374 Crystal Lake, IL

815 270-3374 Crystal Lake, IL

815 770-3374 Crystal Lake, IL

815 200-xyz-xyzx La Salle/Rockford, IL

815 290 La Salle/Rockford, IL

Not sure where they came up with these numbers, as they aren't valid.


When I encounter situations like this, I employ the modem to call out to my cell phone which is equipped with caller id.


I just did a search on the number 101073217709889664 because it is a phone tap detection service. If you call that number from any landline phone, it gives you a number like 8880009880, but the person that gave us this number also had written down the numbers 80000001 next to it, so we dont know if the number 80000001 means you ARE bugged or Aren't. but in any case, thats what the number is for.
Ben G

Tue Apr 5 00:50:43 2005: 274   anonymous

Here's a few more ANAC's Most should read back CPN (calling party number)

877-823-2565 (877-TADA-LOL) This ANAC reads back ANI II digits (line class) check out NANPA for more info..

1800-223-1104 (code : 195632)
1800-532-7486 (there is a message before it reads the ANI, so give it a second)
1800-204-4653 (010809 and then number)
1800-877-2278 (009949 and then number)
1888-221-0104 (enter any 5 digit number)
1800-789-4479 (201867 and then number)
1800-729-0056 (302234 and then number)


Sun Jul 19 15:57:53 2009: 6648   anonymous

so what is this 8880009880 response telling me?


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