| DNIC Assignment | Service | Network operation |
| 4530 | Spare | - |
| 4531 | Spare | - |
| 4532 | Spare | - |
| 4533 | Spare | - |
| 4534 | Spare | - |
| 4535 | Spare | - |
| 4536 | Spare | - |
| 4537 | Spare | - |
| 4538 | Spare | - |
| 4539 | Spare | - |
| 4540 | Public Switched Document Transfer | Hong Kong Telecom International |
| 4541 | Packet Switched Services | Hutchison Communications Ltd. |
| 4542 | Packet Switched Network (IDAS/ITS) | Hong Kong Telecom International |
| 4543 | Packet Switched Services | New T&T Hong Kong Ltd. |
| 4544 | Data Access Switched Network (DAS) | Hong Kong Telecom International |
| 4545 | Packet Switched Network (Datapak) | Hong Kong Telephone Company |
| 4546 | AT&T EasyLink Services | AT&T EasyLink Services Asia Pacific Ltd. |
| 4547 | Packet Switched Services | New World Telephone Ltd. |
| 4548 | Public Value-added Facsimile | KDD (HK) Ltd. |
| 4549 | Spare | - |