| Chennai Telephones |
| Morning Alarm & Reminder Service | 173 |
| Time Announcement in English | 174 |
| Time Announcement in Tamil | 175 |
| Time Announcement in Hindi | 177 |
| Trunk Booking | 180 |
| Assistance / Cancellation | 181 |
| Trunk Information | 183 |
| Phonogram Service | 185 |
| International Calls | 186 |
| International Enquiries/Asst. | 187 |
| Trunk Delay Enquiry | 188 |
| Lightning Call Booking | 189 |
| Trunk Assistance | 191 |
| Directory Enquiry | 197 |
| Repair Service | 198 |
| Local Assistance | 199 |
| Change of Telephone No in Tamil | 1953 |
| Change of Telephone No in English | 1952 |
