| Abbreviation | Definition |
|---|---|
| CAL | Connection Access License |
| CAL | Customer Access Line |
| CALA | Customer Address Location Area |
| CALC | Customer Access Line Charge |
| CALEA | Communications Assistance for Law Enforcement Act |
| cama | Centralized Automatic Message Accounting |
| CAPS | Call Attempts Per Second |
| CAPTAIN | Character And Pattern Telephone Access Information Network |
| CARE | Customer Account Record Exchange |
| CAS | Carrier Activity Sensor |
| CAS | Combined Antennae Services |
| CASP | Communications Application Service Provider |
| CAT | Charges, Access, and Terms |
| CATI | Computer-Assisted Telephone Interviewing |
| CB | Call Back |
| CBCU | Centralized Broadband Control Unit |
| CBO | Call-Back Only |
| CBQ | Class-Based Queuing |
| CC | Call Control |
| CCB | Central Control Building |