CICs identify a carrier. The Carrier Access Code, the actual dialing sequence used by the calling party, incorporates the CIC.
Prior to April, 1993, CICs were assigned for Fg.B and Fg.D access from the same pool. Fg.B CIC codes expanded to 4 digits at that time. I was trying to remember the Fg.B CAC prior to expansion. I thought it was 950-0XXX where X is any digit 0-9. With expansion, 0 was prepended to CIC.
However, checking the NANPA list, there are also 1XXX CICs, suggesting that some three-digit CICs had 1 prepended. Prior to expansion, was the CAC also
950-1XXX for certain carriers?I found a note that 9000 possible CICs can be assigned in Fg.B because switches cannot distinguish between 950-0XXX and 950-1XXX. Can someone explain the conflict?
With Fg.B CIC expansion, 5XXX range was opened. 6XXX range will be opened next, but this range hasn't yet been opened. Then it goes to 2XXX.
In April, 1995, Fg.D codes were expanded to four digits. "0" was prepended to existing codes, and the CAC changed from 10XXX to 101XXXX. I found a note that Fg.B CICs as 4 digits could be reserved for Fg.D assignment after code expansion.
CICs were first assigned in 1981. They were two digits. Were these used for anything more than intercarrier billing and settlements? Were there CACs at the time from any exchange?
CICs expanded to three digits in 1983. Was "0" prepended to existing CICs?
Where and when were CACs first dialable as either Fg.B or Fg.D?
How many 950 prefixes were assigned before its use as Fg.B CAC?