| Abbreviation | Definition |
|---|---|
| CMTS | Cellular Mobile Telephone System |
| CN | Calling Number |
| CNA | Called Number Authority |
| CNA | Cell Not Available |
| C-NBAP | Common Node B Application Part |
| CND | Calling Number Display |
| CNG | Comfort Noise Generation |
| CNM | Customer Network Management |
| CNT | Corporacion Nacional de Telecomunicaciones |
| CO | Central Operations |
| COAM | Customer Owned And Maintained |
| COB | Change Of Billing |
| COBE | Corporate Owned Business Only |
| CoC | Carrier of Carriers |
| COC | Central Office Connection |
| COFA | Change Of Frame Alignment |
| COIC | Central Office Interface Circuit |
| COL | Colorado Online Learning |
| COLT | City Of London Telecommunications |
| COMPANDER | COMpressor/exPANDER |