Path: utzoo!utgpu!attcan!uunet!lll-winken!netsys!vector!nobody From: Miguel_Cruz@ub.cc.umich.edu Newsgroups: comp.dcom.telecom Subject: (none) Message-ID: Date: 5 Jan 89 08:15:58 GMT Sender: chip@vector.UUCP Lines: 41 Approved: telecom-request@vector.uucp X-Submissions-To: telecom@bu-cs.bu.edu X-Administrivia-To: telecom-request@vector.uucp X-TELECOM-Digest: volume 9, issue 5, message 4 Roger Haaheim asks about how to find the ringback number for your switch withot the phone company's help. On most ESS systems, if you set up a reasonably intelligent modem to dial each possible exchange followed by the last 4 digits of your phone number (for instance, if your phone number was 552-4563, then you would write a program to dial 220-4563, 221-4563, etc...) until it hits a dial tone. For instance, for my number, the ringback exchange is 952. If I dial 952 and the last 4 digits of my phone number, I get a dial tone. Then I can hang up for a half second, pick it up, and hang it up again. About 3 seconds later, it will ring. What fun. I think I explained this before (and in just a befuddling fashion), but each physical switch handles one or more logical exchanges. For instance, in Ann Arbor, one switch handles numbers with the prefixes 662, 663, 665, 668, and 930. The "phantom" ringback exchanges generally used by Michigan Bell start at 951. Therefore, for my switch, 662 phone numbers use 951, 663 phone numbers use 952, and so on. Another switch in town handles 994, 995, 996, 761, and 769. 994 numbers use 951 for ringback, 995 numbers use 952, and so on. If you dial your ringback prefix and the last 4 digits of someone else's phone number, you will get a busy signal. Note that there is no guarantee that your BOC will use 95x's for ringback. In fact, there is no real guarantee that your system will be anything like I described. But as far as I know most are. Some older systems have a 2 or 3 digit sequence which you follow by a ring code and hang up to have your phone ring back. Some of the sequences I have seen are 419 and 79. Ring codes are 2 digits, neither of which is a 9 or 0. 11 generates a normal ring, others (23, 46, etc., generate various combinations of short and long rings, apparently for testing party lines). So, in one of these areas you might have to dial 7911 or 41911 then hang up, in order to make your phone ring. [Moderator's Note: The main thing that I do not like about this approach is the ringing of *random telephones looking for something else.* This is just a variation on the programs which search for carrier by dialing everyone else in the community without regard to their desire to be left alone. I do not like 'demon-dialer' software. It causes an invasion of privacy of others. P.Townson]