Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: utzoo!decvax!decwrl!ucbvax!csnet-relay.arpa!JSOL%BUCS20%bostonu.CSNET From: JSOL%BUCS20%bostonu.CSNET@CSNET-RELAY.ARPA (Jon Solomon) Newsgroups: mod.telecom Subject: Rochester telephone service Message-ID: <[BUCS20].JSOL.27-Oct-85.18:36:42> Date: Sun, 27-Oct-85 18:36:00 EST Article-I.D.: <[BUCS20].JSOL.27-Oct-85.18:36:42> Posted: Sun Oct 27 18:36:00 1985 Date-Received: Sun, 3-Nov-85 03:41:18 EST References:Sender: usenet@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 33 Approved: telecom@ucbvax.berkeley.edu Well, basically it is a 3-fold process: 1) your local exchange gobbles up as much of the number as can be processed locally: In Step exchanges this is usually a "1", Crossbar and Electronic exchanges usually gobble the whole number and do their own translation/verification of the prefix (at least for calls within the area code), then it is passed to (2). 2) The local exchange sends the call to a toll switch. Step in this case passes the call as soon as the "1" is dialed. An interface to the toll switch gobbles the rest of the number up and passes it to the toll center using MF tones. The toll center dials a call to the area code chosen, using both LOC and Common Carrier lines (i.e. AT&T, Sprint, MCI, etc), connecting it to (3). 3) The local switch in Rochester then finally gets the call and dials the local number. When the call is answered, supervision gets back to the originating CO to begin billing. "Route Planning" happens usually at the Common Carrier level. At this point, at least, there is no mechanism to do route-planning at the local switch (plans were made at one point to implement that on a local switch, but I think divestiture put a monkeywrench in the plans). Therefore using this model, it is safe to say that your tones don't do much in the process of completing the call. Special tones (not dialable from a touch tone phone -- security in obscurity!) are used to complete calls (except for step by step which dial pulses into the exchange). Hope that helps. --JSol