Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!osu-cis!killer!vector!nobody From: MCHARRY%BNR.CA@MITVMA.MIT.EDU (J.) Newsgroups: comp.dcom.telecom Subject: Calling number delivery Message-ID: Date: 12 Sep 88 12:18:00 GMT Sender: chip@vector.UUCP Lines: 65 Approved: telecom-request@vector.uucp (USENET Telecom Moderator) X-TELECOM-Digest: volume 8, issue 141, message 3 X-Submissions-To: telecom@xx.lcs.mit.edu (Mailing List Coordinator) X-Administrivia-To: telecom-request@vector.uucp (USENET Telecom Moderator) This is a copy of a note I submitted to Risks Digest. It might also be of interest here. I should add that 'CLASS' is a Service Mark of Bell Communications Research. The telephone feature of delivering the calling number to the terminating line is part of a group of features called 'CLASS', although there are other ways it could be done in certain special cases. There are a number of Bellcore publications that describe it in some detail. Among these are TR-TSY-000031 on the basic feature, (TA) 000030 on the signalling between office and customer terminal, 000391 on the feature to block delivery of the calling number, 000218 on selective call reject, and (TA) 000220, also related to selective call reject. TAs are an early version of TRs. If you don't find one in a reference,look for the other. There are several other TRs that relate to these features, but this list should sate most of us. Calling number delivery, selective call reject, and calling number delivery blocking are all involved with the 'Signalling System 7' which is just beginning to be deployed amongst local exchanges, although some of the long distance carriers are much farther along. Among other advantages, SS7 enables the transfer of much more information between network nodes than was previously generally available. This should allow the introduction of many new network services in the near future. On the other hand, CLASS and calling number delivery in particular will not likely become common until large areas are cut over to SS7, since otherwise they would not work much of the time. (Only within the local switching office, or among those that had already implemented SS7) It looks to me like a subscriber to calling number delivery gets telemetry intended to allow display of the number calling concurrently with ringing. I suppose proper customer premise equipment could pick this off and feed it into a computer or use it to determine what to do with the call, eg. route to an answering machine only if not long distance. If the number isn't available, as would be the case if the originating and terminating offices were not linked by SS7, the telemetry sends ten 0s. If the number is available but the originator is blocking delivery, it sends ten 1s. Calling number delivery blocking is itself a CLASS feature that can be set on by a service order or, depending upon the tariffed offering, turned on or off on a per call basis. How it is offered, if at all, is up to the local telco and PUC. The TR makes it look to me like it is not available to party line subscribers. I think there is a technical reason for this. Selective call reject allows the subscriber to set up a list of up to N directory numbers (N might be on the order of 6 to 24) that would be sent to 'treatment' instead of ringing the subscriber's phone. A caller using blocking could be put on this list after one call by using a control that says, in effect, add the last caller to my list, but that number could not be read from the list by the subscriber. It doesn't look to me like the blocking code itself can be put on the list; maybe somebody else knows a way or has tried it. Call reject can be turned on or off also, and can be maintained from either a DTMF or dial phone. There might be something here for everybody. If I can block delivery of my number and Mr. Townson can send me to treatment we would be almost as well off as with Internet addressing from Bitnet to Portal. The foregoing opinions and interpretations are mine, not my employer's. My interpretations of the referenced documents are based on a cursory reading. They probably contain some errors. John McHarry McHarry@BNR.CA (Bitnet) McHarry%BNR.CA.Bitnet@wiscvm.wisc.edu