| NIU Emergency Services | 911 |
| Customer Assistance | |
| - Telephone Repair - Billing Questions - Dialing and Feature Information - Student VoiceMail Information |
753-8100 753-0963 753-7500 753-7505 |
| Local Calls | |
| - NIUCampus | Dial 7-digit number |
| - Local Area (DeKalb, Sycamore, Creston, Genoa, Hinckley, Kirkland, Malta, Maple Park, Shabbona, and Waterman) | Dial 1 + 10-digit number + authorization code |
| Directory Assistance | |
| - NIU | 0# |
| - DeKalb/Sycamore | 1411 + authorization code |
| - All Other Areas | 1 + Area Code + 555-1212 + authorization code |
| Long Distance Calls | |
| - All Areas | Dial 1 + Area Code + 7-digits + authorization code |
| - International | 011 + Country Code + City Code + Local Number + authorization code |
| 800/888/877/866 Calls | |
| - Toll Free | Dial 1 +(10-digit number) + authorization code |
| Credit Card/Phone Card/Collect/Operator Assisted Calls | |
| - Domestic | 0 + Area Code + 7 - digit number |
| - International | 01 + Country Code + City Code + Local Number |