I no longer have a copy of the ground-start interface spec we once wrote in Committee T1 but could swear that there was dialtone involved. However, I now understand what you mean by blind dialing.
This refers to terminal equipment that is not willing or able to detect dial tone and operates on the faint hope that after some time, any Central Office will eventually acknowledge a request for service and be able to receive address signaling. When the first automatic dialers were designed, there was no standard in Nprth America for dialtone and the range of signals that could be dial tone was quite spread. Therefore, all sorts of things that were not dialtone, could be mistaken for dialtone. There was a fear that a proliferation of these blind dialers could start tying up Central Office Common equipment resulting in poorer service to customers that would not dial before they received dialtone. This never really happened because the COs all switched to standard dialtone, which makes dialtone detection much less ambiguous. In addition, the cost of providing dialtone detection came down so far that it became a non-issue for any piece of equipment that was of "some" quality. However, a new phenomenon is taking place, INTERNET. I've been given to understand that in some areas of the Silicon Valley, so many people are tying up their lines by sitting on the INTERNET, that one in 6 call attempts fail, because the CO does not return dialtone when a request for service is made. (Central Offices are designed on well researched assumptions on how many of the subscribers will be using the phone. Not all subscribers can be served simultanuously). Even if the equipment could serve all subscribers, that would be sort of pointless because all the calling party would get would be a busy signal. Will the permanent INTERNET users switch to their cable TV companies, for INTERNET service ??? For the time being, I would not invest a great deal of money in automatic dialing equipment that can not detect dial tone. It may not be a viable product. Ciao, Vic
