johnl@ima.ISC.COM (01/08/89)
In article <telecom-v09i0005m04@vector.UUCP> Miguel_Cruz@ub.cc.umich.edu writes: >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 ... > >[Moderator's Note: The main thing that I do not like about this approach >is the ringing of *random telephones looking for something else.* ... Clearly the ringback prefix can't be the same as a valid exchange or you couldn't call anybody in that exchange. Program your modem to call only the unassigned prefixes to avoid pestering people. Most local phone books have a list of assigned prefixes in the local NPA. I also note that telcos often use a range of prefixes, e.g. in New Jersey they use 550 to 559 excepting 555. If you look at the assigned prefixes and see ten in a row that are unused, that's probably it. -- John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 492 3869 { bbn | spdcc | decvax | harvard | yale }!ima!johnl, Levine@YALE.something You're never too old to have a happy childhood.
dmr@csli.Stanford.EDU (Daniel M. Rosenberg) (01/10/89)
In article <telecom-v09i0007m05@vector.UUCP> johnl@ima.ISC.COM writes: >I also note that telcos often use a range of prefixes, e.g. in New Jersey >they use 550 to 559 excepting 555. If you look at the assigned prefixes >and see ten in a row that are unused, that's probably it. >John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 492 3869 At least as of a few days ago, 550-xxxx, where xxxx are the last four digits of your phone number, will do ringback in North Jersey (201). This does not work for (most, if not all) payphones (but when it did, it was a favorite trick for the kids to leave the phone ringing in the Foodtown). -- ## Daniel M. Rosenberg /////// CSLI/Stanford //////////////// +1 (415) 328-1373 ## INTERNET: dmr@csli.stanford.edu //////////// UUCP: {ucbvax, decvax}!csli!dmr ## I've my opinions, Stanford theirs. I don't speak for them, nor they for me.#