Area Codes 312 & 872
Telephone Central Office Building Pictures

The following are representative examples of telephone central office buildings in Area Code 312 and 872 (Inner City Chicago, Illinois).

Click on the pictures below for a larger version.

Chicago Zone 01 "Calumet"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILCADS0 CHCGILCADS1 Switch Type: DS0: Nokia/Alcatel/Lucent 5ESS DS1: Ribbon/Genband/Nortel DMS-100 Prefixes Served: DS0: (312) 326, 328, 528, 567, 570, 674, 791, 808, 945 DS1: (312) 225, 842, 949 Notes: Source: GSV
Chicago Zone 01 "Canal"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILCLDS0, 3 Switch Type: Nokia/Alcatel/Lucent 5ESS Prefixes Served: (312) 258, 441, 463, 474, 627, 632, 715, 756, 876, 879, 887, 912, 928, 993 Notes: Source: GSV
Chicago Zone 01 "Dearborn"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILIDDS0, 2 Switch Type: Ribbon/Genband/Nortel DMS-100 Prefixes Served: (312) 222, 229, 245, 321, 396, 464, 527, 595, 742, 744, 755, 817, 822, 828, 832, 836, 840, 923, 970 Notes: Source: GSV
Chicago Zone 01 "Franklin"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILFRDS0,1,2,3,4 Switch Type: Nokia/Alcatel/Lucent 5ESS Prefixes Served: (312) 201, 220, 230, 251, 267, 325, 357, 368, 443-4, 542, 553, 556-7, 592, 603, 606, 629-30, 641, 759, 797, 812, 849, 855, 857, 899, 984 Notes: Source: GSV
Chicago Zone 01 "Lakeshore"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILLRDS0 Switch Type: Ribbon/Genband/Nortel DMS-100 Prefixes Served: (312) 228, 233, 240, 297, 374, 472, 540, 552, 565, 616, 653, 729, 819, 856, 861, 938, 946 Notes: Also known as AON Center. Source: GSV
Chicago Zone 01 "Monroe"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILMODS0 CHCGILMODS1 Switch Type: DS0: Nokia/Alcatel/Lucent 5ESS DS1: Ribbon/Genband/Nortel DMS-100 Prefixes Served: DS0: (312) 421, 433, 491, 572, 633, 710, 738, 829, 850 DS1: (312) 226, 243, 355, 361, 413, 432, 455, 492, 563, 569, 666, 733, 743, 746, 864, 942, 996-7 Notes: Source: GSV
Chicago Zone 01 "Superior"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILSUDS0,2 Switch Type: Nokia/Alcatel/Lucent 5ESS Prefixes Served: (312) 335, 417, 440, 534, 587, 654, 751, 790, 867, 932, 979 Notes: Source: GSV
Chicago Zone 01 "Wabash"	Listing Updated: July 2018 Operating Company: at&t/SBC/Ameritech/Illinois Bell CLLI: CHCGILWBDS0,2,3 Switch Type: Nokia/Alcatel/Lucent 5ESS Prefixes Served: (312) 353, 362, 385, 408, 427, 435, 554, 582, 692, 697, 732, 789, 823, 886, 939, 983 Notes: Source: GSV

Visit other Illinois Area Codes: 217 309 312 618 630 708 773 815 847

Visit nearby regions: Indiana Iowa Kentucky Missouri Wisconsin