The 312 and 773 area codes have officially gone vintage. Make way for 872.
In July, the ol' 773 reached “exhaust,” meaning there are no more unassigned numbers available with the 773 prefix.
312 tapped out in '95.
The 312 area code currently serves the immediate downtown and Loop areas and the 773 area code serves the northern, western, and southern neighborhoods of Chicago. 872 will do both, with the three-digit prefix popping up in both area-code service areas.
Those who already have a 773 or 312 area code can keep both their current area code and phone number. It's new phone customers that will be assigned the 872 area code.
But no one will go completely unaffected by the change. When 872 starts being used, all phone calls made in the overlapping areas will be required to use a 10-digital number (1 + area code + phone number). Even if neighbors have the same area code, the 10 digit code must be used according to a mandate by the FCC.
The first 872 numbers will go into service on November 7, 2009. There will be a 90-day period for customers to acclimate to the additional dialing pattern before the new area code launches.
The city's a'growing, Chicagoans, and so are its number of area codes.