With all due respect, the identification came from an identification wire which was threaded through a "Number Network" frame with oval openings corresponding to the digits of the number and surrounded by coils which could detect a spurt of tone on the idenficiation lead. This spurt was sent when a caller accessed the DDD equipment.
An object lesson given to planners for later 5XB/DDD cutover committee involved a jumper that was misrouted in the Enid, Oklahoma, office its cutover to 5XB/DDD/AMA (previously it had been manual common battery).
A jewelry store which sold small appliances and a lumber yard which sold large appliances were frequently in dispute over their toll billing.
The problem was compounded by the fact that both called the same General Electric appliance distribution warehouse in a suburb of Kansas City to place orders or for other dealings. Neither one of them could deny they made calls to this number, since they both did, but not necessarily at the times the were billed for.
This went on for months. A craftsman investigating the problem for the umpteenth time ran the identification jumpers and found the jumper for one of the business's second line was miswired to one of the other business's numbers. (The numbers at one point differed by only one digit. Since it was only on the second line, the occasions of misbilling appeared to be random.
A caution to switchmen to verify every jumped before cutover to make sure that they or the W.E. installers had each one wired correctly.
Incidentally, group billing takes place in the accounting office, not in the C.O., so each line is wired to its correct line number, not kludged in the C.O.
Wes Leatherock snipped-for-privacy@aol.com