covert@covert.enet.dec.com (John R. Covert 15-Nov-1990 0851) (11/15/90)
>I've just tried to dial a number in the 917 area code (non existent >yet) from France. I got a French intercept message just after dialing >the 7 of 917 saying that this code was not in service. What means has >a switch in France to know that. International exchanges in foreign countries must have a table of area codes in World Numbering Zone 1 in order to know whether to send calls to the Canadian international exchange (in Montreal), to one of AT&T's gateways in New York, Pittsburg, Denver, Atlanta or Sacramento (or to a gateway for another carrier if multiple carriers are providing two-way service), or to the gateways in Honolulu and Anchorage for calls to Hawaii and Alaska. In addition, for area code 809, they must do six-digit translation in order to send traffic to the appropriate island or country. There is not a single point where all other countries may send 809 traffic. A determination must be made as to whether to send traffic to Bermuda, Puerto Rico, St. Kitts, etc. Also, even where traffic to multiple destinations may be permitted to transit through a third country which does additional routing translation, in countries where charging is done by charge pulses (almost all countries outside North America), the appropriate rate has to be computed before the call can be placed by determining which of the above destinations is being dialled. This can only be done by knowing where each area code is, and for area code 809, knowing where each exchange is. BTW, since I brought up multiple carriers: The CCITT recommendations specify what to do about multiple carriers. Since customers in countries having circuits to and from the U.S. provided by multiple U.S. carriers don't have a way of selecting ATT/MCI/Sprint for calls to the U.S., the rule is that outgoing traffic is to be statistically assigned to each carrier based on the same percentages as the incoming traffic. john