linneweh@uunet.uu.net (Louis Linneweh) (01/11/91)
forrette@cory.berkeley.edu (Steve Forrette) writes: >automatically find me. Someone has to dial into the roamer port, then >enter my 10 digit number to reach me. The problem is that if they are >calling long distance, they must pay a toll charge for each attempt, >whether or not I'm on the air, since the call supervises at the point >the secondary dialtone is provided. Some suppliers of cellular switches do allow the system operator to configure the ROAM trunk group to delay answer supervision until the called party (or the voice message system or the party to which the call was transfered) answers. However, if the call is delivered by an Inter-Lata carrier, the carrier may not cut through the forward audio path (from caller to called) until answer supervision is received as a method of fraud prevention. This would prevent the End-to-End DTMF from being received by the cellular system. Therefore, the cellular operator must configure most incoming trunk groups for immediate answer supervision since the source of the call is normally not known. When the cellular system operator has a sufficiently sophisticated (read "large") operation, they may be able to separate the incoming traffic on unique trunk groups (such as with direct connections to the offending IC) so that only those networks that require immediate answer supervision get it. From the carrier's point of view the caller reached the destination that was requested (the ROAM port) and they feel justified in getting paid. Certainly, business arrangements could be reached between a cellular operator and the carriers to avoid this problem if it was of sufficient importance. >Since cellular is provided through DID or some other method whereby >the cellular switch appears as the "end office," why can't the >supervision be done based on when the call is actually answered? US >Sprint manages to do precisely this with their FONcard system, >overcoming any technical or legal hurdles. You enter the called >number and your FONcard number, all without supervision taking place. Cellular service providers are at the wrong end of the connection, i.e. after the IC has done its thing, in the situation that causes concern. In the case of a FONcard, the cost of the call to the carrier will be paid for by the carrier as soon as the carrier connects. >I guess part of the answer is that the people affected by this problem >are not the cellular carrier's home customers, but only associates of >roamers from other systems. But whatever happened to just wanting to >do it right for the sake of it? It seems that especially cellular >carriers are not apt to do anything that doesn't increase airtime >revenues. I'm sure something would be worked out if the cellular operator's customers thought it was important enough to take their business elsewhere. The real "right thing" will only happen when the carrier enters the process of finding the mobile (instead of being done when the ROAM port is reached).
DREUBEN@eagle.wesleyan.edu (Douglas Scott Reuben) (01/12/91)
Hi- In article <15877@accuvax.nwu.edu>, forrette@cory.berkeley.edu (Steve Forrette) writes: When roaming in a foreign system: > ...[S]omeone has to dial into the roamer port, then > enter my 10 digit number to reach me. The problem is that if they are > calling long distance, they must pay a toll charge for each attempt, > whether or not I'm on the air, since the call supervises at the point > the secondary dialtone is provided. > Since cellular is provided through DID or some other method whereby > the cellular switch appears as the "end office," why can't the > supervision be done based on when the call is actually answered? I'm by no means an expert on DID, but I can tell you that there WERE many ports that did NOT return supervision, although few, if any, remain. For example, Cell One/San Francisco, until maybe mid-July this summer (1990) did NOT return supervision until the called mobile party answered. When they changed this, I called them to find out why, and they told me: "Oh, so customers can press the "#" button down if they make a mistake when dialing in the number. Otherwise, when you call with a Calling Card, you will be disconnected." Quite true, but I don't think this is the reason. I recall discussion on the Digest about this in perhaps late-1987 to early-1988. From what I gathered, AT&T used to allow this sort of signalling to go through. IE, the talk path would be open BOTH ways, even before supervision was returned. Thus, a caller calling a roam port (or anything else, like an automated PBX attendant which accepted Touch Tones), would hear the dial tone, AND be able to Touch Tone in the desired mobile number. When the mobile answered, supervision was returned, a billing for the call commenced. If the mobile was unavailable, then no supervision would be returned, and the caller would not be billed for the call to the roam port. However, according to the postings (and this is quite hazy, so please DO correct me here), AT&T installed a new system in their 4ESS(?) toll-switches, which didn't allow for the CALLED party (ie, the roam port) to hear the calling party (ie, the person entering the touch tones) UNTIL supervision was returned. That is so say, TWO-way conversations commenced AFTER supervision, not before, as had been the case. You could still hear the party you were calling, but they couldn't hear you until their end sent out a supervision "wink" (or whatever). I don't recall any stated outstanding reason for this, although a few were presented. Some mobile systems didn't seem to realize this. For example, Cell One/South Jersey (New Jersey) used to have non-supervising ports at 201-715-7626 and I think the other was 609-575-7626. In the Spring on 1990, they changed the numbers (why I don't know), to 908-610-7626. This new 908 port worked the same way the old ones did, ie, did not return supervision UNTIL the called party actually answered. Yet for some reason, the new port worked under the "new" AT&T "rules" (no callING to callED party conversation until supervision), so if you called via AT&T, you COULD NOT ENTER *ANY* TONES! Callers in New Jersey for the most part were fine, as NJ Bell doesn't seem to care about supervision. Also, callers over MCI and Sprint didn't notice this, either, as they appear to work differently than AT&T. It was VERY difficult to convince Cell One/South Jersey that *I* was correct that their port was "not working", since each time they called in locally (via NJ Bell, not AT&T) it worked just fine! And they even had MCI (their LD co, it seems) call them to try it out, and MCI reported no trouble. I finally had to three-way them to let them hear what was going on. Eventually, they changed the port to automatically return supervision. This sort of spoiled it for non-AT&T customers, ie, those coming in over NJ Bell or some non-AT&T LD Co. Previously, they could access the port for free, unless, of course, the mobile was active and answered the phone. Now, all calls are billed, regardless of an answer. The Cell One/South Jersey port covers a wide area (DMX), from New York City's Metro One system, to North Jersey (Metro One), to South Jersey/Trenton (Cell One), to Atlantic City/Vinland (Cell One), to Phil (Metrophone) and Wilmington, DE, (again, Cell One.) Thus, the port was quite useful to me, as I could tell people to call me at ONE roam port, and I could be reached from all of lower New York all the way down to about 20 miles north of Baltimore, where the DC system takes over. Now, since I may very well not be available, I don't want people to keep trying to and paying for each call, which they wouldn't have had to do otherwise. In any event, it seems that such systems are fading quickly as they are replaced by newer ports that appear to be subjected to the "new" AT&T supervision rules. I'd like to hear about any ports that still work the "old" way, and of course, any corrections on my rather sketchy description of AT&T's switching system. Doug dreuben@eagle.wesleyan.edu // dreuben@wesleyan.bitnet
charris@uunet.uu.net (Craig Harris) (01/12/91)
In article <15877@accuvax.nwu.edu> forrette@cory.berkeley.edu (Steve Forrette) writes: X-Telecom-Digest: Volume 11, Issue 15, Message 4 of 9 >This is something that has always bothered me. Let's say that I'm >roaming into a far away cellular system where my calls don't >automatically find me. Someone has to dial into the roamer port, then >enter my 10 digit number to reach me. The problem is that if they are >calling long distance, they must pay a toll charge for each attempt, >whether or not I'm on the air, since the call supervises at the point >the secondary dialtone is provided. The reason for the answer supervision on roamer access numbers is that some of the time AT&T will not pass audio from the calling party to the terminating party until there is answer supervision. If the Cellular switch did not return supervision, the calling party would not be able to DTMF overdial your mobile number to the roamer access port. This was not always the case. A few years ago, some of the long distant companies that were buying time from AT&T would not send supervision, but would actually complete the call and they could not bill for those calls. So, this was their fix to always make sure that supervision was returned before connecting the audio path from the calling party to the terminating party until answer supervision was returned. Craig Harris, Motorola Inc 1501 W. Shure Drive, IL27-2237 ...!uunet!motcid!charris Arlington Heights, IL 60004-1497
forrette@cory.berkeley.edu (Steve Forrette) (01/14/91)
In article <15963@accuvax.nwu.edu> you write: >In article <15877@accuvax.nwu.edu>, forrette@cory.berkeley.edu (Steve >Forrette) writes: >When roaming in a foreign system: >> Since cellular is provided through DID or some other method whereby >> the cellular switch appears as the "end office," why can't the >> supervision be done based on when the call is actually answered? >However, according to the postings (and this is quite hazy, so please >DO correct me here), AT&T installed a new system in their 4ESS(?) >toll-switches, which didn't allow for the CALLED party (ie, the roam >port) to hear the calling party (ie, the person entering the touch >tones) UNTIL supervision was returned. That is so say, TWO-way >conversations commenced AFTER supervision, not before, as had been the >case. You could still hear the party you were calling, but they >couldn't hear you until their end sent out a supervision "wink" (or >whatever). I don't recall any stated outstanding reason for this, >although a few were presented. Yes, this makes perfect sense. So, the big question is, why did AT&T decide to change this? There must have been some fraud going on somewhere, I suppose. But, as I understand it, a DID customer can get in big trouble for doing bad things with supervision. You would think that it would be easier to go after the few people abusing the system than to change their toll network. And I'm sure that this would be one issue where AT&T would have the full cooperation of the local telco. Didn't AT&T think that this new setup may be a problem to someone? Imagine what would happen if the local telcos did the same thing. Suddenly, no long distance carrier's calling card services would work, as they normally don't supervise until the actual call is answered. Surely, AT&T wouldn't like to have to change THEIR system because of a local telco change, but it's okay to force the cellular carriers to do just that. I'm really surprised that this is coming from AT&T - it just smacks of something one of the "other guys" would do, doesn't it? Steve Forrette, forrette@cory.berkeley.edu