Vic, You may have become american-ethno-centric in your dotage, but if memory serves me well a ground start telephone system does not use dial tone to dial. In this system both ends of the local loop recognize there local current. The terminal detects there is current when it goes off-hook and the central office equipment detects the loop is off-hook by detecting loop current. The CO then conditions it self to except dialing. Usually pulse dialing.
I think what Ingrid is asking about is blind dialing. This is a mode of dialing that has been in use as long telephones. It in essence means going off-hook, waiting for a period time and then dialing. This is sans making any effort to detect the presence of dialtone before dialing. We really need more information before it can be determined if Ingrid is asking about really blind dialing. Regards, Duane >> Obviously, "blind dialing", is >> dialing in the absence of dial tone. Recalling >> my modem days, some countries prohibited this >> activity. Others allowed it, but may also >> require you to recognize their dial tone when >> you were not in blind dial mode. Why would it >> be prohibited? A) Someone could already be >> talking on that line you've seized (hence, no >> tone); B) The exchange cannot place your call >> (recognize your DTMF) until it is ready to do >> so, ie has sent dial tone, you'd be tying up >> a line on a call that can't go through. In some >> countries, dial tone is not present for several >> seconds*, without "wait for dial tone", or a >> pause inserted in the string, most dial attempts >> would be unsuccessful. > >In any telephone exchanges I know off, taking the >telephone off-hook, or otherwise terminating the line >with a suitably low impedance, is known as a request >for service. > >The exchange acknowledges that request for service >by providing dialtone. That is all dialtone is, an indication >that the central office is now prepared to accept address >signals. > >If you dial before the CO is ready, you won't get the number >you were trying to reach. That is a self correcting problem. >Don't know why it should be prohibited. > >Ciao, > > >Vic
