Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-lcc!ames!ucbcad!ucbvax!ut-sally.UUCP!uucp From: uucp@ut-sally.UUCP (Unix-to-Unix Copy) Newsgroups: comp.dcom.telecom Subject: Submission for comp-dcom-telecom Message-ID: <8705030206.AA25922@sally.utexas.edu> Date: Sat, 2-May-87 22:06:19 EDT Article-I.D.: sally.8705030206.AA25922 Posted: Sat May 2 22:06:19 1987 Date-Received: Sun, 3-May-87 09:23:32 EDT Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 78 Approved: telecom@xx.lcs.mit.edu Path: ut-sally!utah-cs!utah-gr!uplherc!nrc-ut!nrcvax!ihm From: ihm@nrcvax.UUCP (Ian H. Merritt) Newsgroups: comp.dcom.telecom Subject: Re: 2600 "fraud" detection Message-ID: <894@nrcvax.UUCP> Date: 1 May 87 16:03:01 GMT References: <12298260996.77.AWALKER@RED.RUTGERS.EDU> Reply-To: ihm@minnie.UUCP (Ian Merritt) Distribution: world Organization: The Frobboz Magic Dungeon Co., Inc. Lines: 66 >Isn't this a bit redundant in these CCIS-ridden days? > >Also, it seems rather improper for an office to assume that any occurrence of >2600 on a subscriber loop indicates possible fraud. First of all, if someone >wanted to defraud he'd just hike down to the nearest pay phone. Second, there >are a lot of OCC switches that respond to 2600, so the phone co has another >think coming if they believe I'm committing toll fraud every time I clobber >one of them upon completion of a call. Fooey. > I think you may be drawing incorrect conclusions from your observations. Are you a known paranoid? (:->) Your initiial comment about CCIS is more realistic. In this day of CCIS, with the local telcos no longer concerned with interstate fraud anyway, particularly with respect to the non AT&T carriers using equipment that's doesn't fully interface with the network, I would be hard-pressed to believe that any of the local telcos still have any such equipment. It sounds as if your observations can be explained as follows: >The user-end symptoms of 2600 detection seem to be as follows: Beeeep. Switch 2600Hz >disconnects your call, or whatever its fancy. Disconnect is due to the effect of 2600 on the cheap long distance carriers equipment; not some fancy fraud detection. > [...] Some switches drop the >connection to the office completely, forcing the call to throw back to the >office and return dial tone within a few seconds. New ESS software disconnects faster. Some of the newer CO <-> Cheap LD carrier trunk interfaces provide more signalling information to detect drop faster. > [...] At any rate, in the >background one can hear a small "grack" sort of click -- I would assume that >this indicates the bridging-in of the more sophisticated "fraud detection" >equipment that would listen for and report various other tones. Probably bogus assumption. If you were the called party and your line is #1/1A ESS, the click you describe as "grack" sounds like the normal called party disconnect sound; If you were the calling party you might hear something similar when the mechanical junctors in the several older switches involved in the connection drop in rapid succession. On other switches complex sequences of clicks are common for similar reasons, particularly #5 crossbar. I would have to actually listen to it to identify exactly what it was. > [...] This is >un-bridged again after about 20 seconds if nothing else happens. I could >determine this because in some offices the bridging equipment is flakey and >introduces extra line hum while it's connected. In some offices (#5 Crossbar), when you are dropped from a connection you spend some time on a holding circuit that happes to provide you with substantial induction noise, for your listening pleasure. Generally this condition does not connect any detectors to the line other than the usual ROH (Receiver On Hook) detect. It usually lasts about 10 to 20 seconds. Try dialing out from that same office. Listen closely after breaking dialtone and see if you don't hear this noise. You can easily tell if it's crossbar if shortly (.2 to .9 second) after dialing your last digit of a valid sequence, you hear a loud clunk after which there is no more induction noise. Cheerz... --i