Mailinglist Archive: opensuse (770 mails)

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Re: [opensuse] connecting my telephone to the internet
James Knott wrote:
Carlos E. R. wrote:
On the other hand, do you remember those movies where the bad guy makes a phone call to the
police and the call has to last less than 20" or he is identified? That's rubbish, you are
identified on on the first second, while ringing, at least on countries like Spain.

Actually, it didn't used to be rubbish. I have worked in telecom going back 40 years and at one point early in my career, I actually worked on some of the old step by step relay systems and even learned to trace calls through them. There's no way it could be done in only 20 seconds. Modern, SS7 sytstems are of course quite different. Also, the phone ID can be spoofed. I get plenty of telemarketing calls where that is done. The originating switch or PBX is the one that provides the ID and it can be set to anything. For example, according to my phone's log, I received a call on Aug 10 from 10000000000. That is in no way a valid number, yet it managed to reach my phone. This is via a regular phone company that provides my home phone. Also, a few years ago, I worked on a phone system where the customer insisted there be no caller ID on outgoing calls, as it was for a woman's shelter and they didn't want anyway for someone to track where those women were. I have also set up VoIP PBXs, where someone in one location could call through another location and appear as though they originated at that 2nd location. It's not at all difficult to do with today's equipment, so accepting from the phone company is not quite as secure as you think.

Further on this. I have a fair bit of experience with the Adtran 550 series multiplexer. This device can connect to a variety of devices and services by plugging in the appropriate interface cards and making the appropriate configurations. I could take a DS1 (T1, E1) from the phone company and assign the channels as I desire. I could have local phones connected or as on one project, I could send voice lines via ISDN, that actually travelled back over the DS1 and on to some other location. The phone company would have absolutely no idea that I had done that or where the other location was. I'd then pick a number, including something like that 10000000000 number I mentioned and it would show as the caller ID. So, not even the police would know where that remote phone was located, as the phone company could not trace it beyond the end of that DS1 trunk. Normally, however, I would give that phone a proper phone number out of the customer's block of numbers. I have extended phone systems on many occasions, sometimes hundreds or even thousands of kilometres┬╣ from where the calls actually appear on the phone network. With some types of equipment, the user could even move their office phone to anywhere they had a decent internet connection or even an analog dial up phone. So, between moving the phones and providing dummy numbers, you really have no idea where an incoming call might be coming from, even though it comes to you via the local phone company.

1) Take a look at a map of Canada. I have extended phones as far a from near Toronto Ontario to Nova Scotia, about 1300 Km or Sarnia Ontario to St. John New Brunswick, over 1700 Km.

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