| Abbreviation | Definition |
|---|---|
| IMPACT | Integrated Message Processing And Communications Technology |
| IMS | Infrastructure Management Services |
| IMT | Inter Machine Trunk |
| IMTS | Itinerant Mobile Telephone Service |
| INAP | Intelligent Network Application Protocol |
| INET | Information Networking Education and Transaction |
| INFRA | INFRAstructure |
| INI | Inter-Network Interface |
| INIT | Initial |
| INN | Inter-Node Network |
| INR | Internet Not Responding |
| INRT | Intermediate Node Reply Token |
| INS | Information Network Services |
| INS | Internet, Networking & Security |
| INS | Interoperable Naming Service |
| INSS | Integrated Network Support System |
| INTERNET | International Networking |
| INTR | Interactive Networking Tool for Research |
| IOB | Input/Output Bridge |
| IOCB | Input/Output Control Block |