| Abbreviation | Definition |
|---|---|
| CGMP | Cisco Group Management Protocol |
| CGSA | Cellular Geographic Service Area |
| CH | Channel |
| CHTS | Communications Hub Technical Specification |
| CI | Communications Integrator |
| CI | Congestion Indication |
| CIA | Complex Interface Adapters |
| CICS | Communications Interface And Control System |
| CID | Client Information Database |
| CID | Cloud Infrastructure Design |
| CID | Customer Interface Device |
| CIDR | Classless InterDomain Routing |
| CIDR | Classless Inter-Domain Routing |
| CIE | Cinnabar Island Email |
| CIL | Configuration Item List |
| CIM | Compuserve Information Manager |
| CIM | Connection Initiation Message |
| CIM | Control Interface Module |
| CIMA | Carrier Interference Multiple Access |
| CIMD | Computer Interface to Message Distribution |