Topics: Why do some ladies on online dating sites still view my profile even after we exchange phone?
These are contributions which were sent to me for this project, which dealt with the historical background of exchange names. This information forms the basis for many of the conclusions I've drawn about the history of exchanges. Much of this information is very difficult to find, and I am greatly indebted to everyone who's taken the time to send it. Thanks!
In the earliest days of phone exchanges, the first *three* letters were used, followed by four numbers. The switch to two letters was very early, but with very old exchanges like SPRing -- SPring 7, you can see the pattern.
For your further information, I know that some Paris telephone exchanges used to be identified by name, using three-letter codes. You can still see from time to time there old signs giving the phone number as, for example, ELYsee 12-34 (that was when they used 7-digit numbers. Now they use 8 digits; everything in the city got a '4' prefix.)