Path: utzoo!attcan!sobmips!uunet!seismo!sundc!newstop!sun-barr!cs.utexas.edu!samsung!rex!wuarchive!texbell!vector!telecom-gateway From: w_smith@wookie.enet.dec.com (Willie Smith, LTN Components Eng.) Newsgroups: comp.dcom.telecom Subject: Calling Number Delivery According to Bellcore Message-ID: Date: 15 Nov 89 22:36:58 GMT Sender: news@vector.Dallas.TX.US Lines: 117 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 515, message 1 of 6 This is not an attempt to start the CLID wars and associated ratholes that so clogged this Digest in the past few months. On a more technical bent: I got the Bellcore Technical References (thanks to the reader who sent in the pointer!) for: CLASS (SM) Feature: Calling Number Delivery TR-TSY-000031 which is the technical spec on how CND (widely discussed in TELECOM as Calling Line ID) works, and; SPCS/Customer Premises Equipment Data Interface TR-TSY-00030 which is the low level details of how the data gets over the phone lines from the telco to your house. They are about $25 each from Bellcore (201) 699-5800 [there's also a toll-free number, but I don't seem to have it handy], and are well worth the price, as they answer a lot of the questions that come up in this Digest. Anyway, I've got a few observations and questions: 1) The basic interface is a 1200 baud FSK data stream between the first and second rings. The interface is not supposed to work in an off- hook state, though it might be interesting to see if they really work that way. All kinds of spoofing might be possible if the box depends on the fact that the CO will not send data when the phone is off-hook... 2) You need a computer to decode the data, as there's a fair amount of complexity, including a checksum and multiple messages. The interface is kind of general, so you could do several different things with it. One use that seems built into the spec is message-waiting (as used in hotels). Does anyone know any other uses? Is it worth making a transciever (so you can talk back to the telco) or should you only bother with a reciever if you are going to 'roll your own'? If you have a computer, you could build the interface (a simple FSK modem) pretty cheap! Does anyone know if any of the commercial units have an RS-232 output? 3) CND (CLID) is available in two different flavors, "subscription" is the usual one, where you sign up for it once, CND is used for all calls into your house, and you are billed (I assume) monthly. The other option is "usage-sensitive", where you still have to sign up for the service (and I imagine pay a connection fee), but you can turn it on and off at will by dialing *65 or *85 (on and off respectively, numbers may vary in your area). This service appears to be billed on a 'number of CNDs sucessfully delivered'. Why would anyone use the "usage-sensitive" option? 4) The calling directory number, "if available and can be disclosed", is transmitted to you. See TR-TSY-000391 for details on blocking. I'm not that concerned about it, but if you are, spend the $25 or so and get the info from the source. Then maybe we can have a reasoned discussion with facts and such. Nawww.... :+) 5) Here's an interesting option I don't remember hearing discussed. The calling party can dial a 4-digit (or longer) PIN that will be displayed instead of the calling DN. This brings up some rather interesting questions on spoofing or hiding your number, does anyone know if the commonly used boxes differentiate between DN (directory number) and PIN? I believe it's in the low-level protocol, but it would appear to be implementation-dependent as to how it's displayed. 6) Another neat future use mentioned in passing is an interface to directory assistance or another database to provide calling party name instead of calling DN. Yes the low level spec will pass ASCII, do any of the current boxes allow display of alphanumerics? 7) The requirement for a customer initiated testing number is "desirable". This would allow the customer to dial a special number, hang up, and get a series of test transmissions (display each digit in each position, etc). Do any of the CND trials out there provide such a service? 8) The various call forwarding options send the originating number to the far end. In other words, a call from A to B that gets forwarded to C should deliver A's number to C. 9) Automatic Callback is the only instance I found where the CND shows a 'private' number. This section is a but hard to describe, but basically: [See TR-TSY-000215 for more information] If I call someone with an unlisted number (I already know their number!) then fire up AC, when the connection is made and I get a special ring signal, that number shows up on _my_ box (so I know who I'm calling back). If I didn't put the number in in the first place and it's a 'private' number, then I'll get a privacy indication. 10) In a Centrex, you may only get the extension number on your box. Anyway, they seem to have thought this all out pretty carefully, and it's a very well written set of documents, so if you have more questions, you can try Emailing me, but the definitive answers are directly available. Kind of pricey if you get all the associated documents, but that's life. I called New England Telephone to try to figure out when this feature would be available in my area, but the customer service rep didn't know what I was talking about. In fact, references to Bellcore didn't seem to ring any bells with her either (sorry :+). She went away for a while doing some research on the question and came back with the response that they had no idea when that might be available on (508) 369-xxxx, but if I call back when the strike is over and they get back on their feet, they might have a better idea.... This has nothing to do with my employer! Willie Smith w_smith@wookie.enet.dec.com w_smith%wookie.enet.dec.com@decwrl.dec.com {Usenet!Backbone}!decwrl!wookie.enet.dec.com!w_smith