Telecommunications Signaling

| AAL | ATM Adaptation Layer |
| AC | Application Context |
| ACK | Acknowledgement |
| ACM | Address Complete Message |
| ACSE | Association Control Service Element |
| ACU | Acknowledgement Signal Unit |
| AE | Application Entity |
| AL | Alignment |
| ANS | Answer |
| AP | Application Part |
| APDU | Application Protocol Data Unit |
| ARP | Address Resolution Protocol |
| ASE | Application Service Element |
| ATM | Asynchronous Transfer Mode |
| AU | Access Unit |
| B | Broadband |
| BA | Buffer Allocation |
| BA | Basic Access |
| BC | Bearer Control |
| BIB | Backward Indicator Bit |
| B-ISDN | Broadband ISDN |
| B-ISUP | Broadband ISDN User Part |
| BSN | Backward Sequence Number |
| BSS | Base Station System |
| B-STP | Broadband Signal Transfer Point |
| BT | Beginning Tag |
| C | Confirmed |
| C/R | Command/Response |
| CAS | Channel Associated Signalling |
| CC | Call Control |
| CC | Connection Confirm |
| CC | Credit Card |
| CCBS | Completion of Call to a Busy Subscriber |
| CCF | Call Control Function |
| CCITT | International Telegraph & Telephone Consultative Committee |
| CCS | Common Channel Signalling |
| CCSS6 | Common Channel Signalling System No. 6 |
| CCSS7 | Common Channel Signalling System No. 7 |
| CD | Call Deflection |
| CDMA | Code Division Multiple Access |
| CFB | Call Forwarding on Busy |
| CFNR | Call Forwarding on No Reply |
| CFU | Call Forwarding Unconditional |
| CIC | Circuit-Identity Code |
| CLB | Clear Back |
| CLF | Clear Forward |
| CLI | Calling Line Identity |
| CLIP | Calling Line Identification Presentation |
| CLIR | Calling Line Identification Restriction |
| CLP | Cell Loss Priority |
| CM | Configuration Management |
| CMIP | Common Management Information Protocol |
| Comp | Component |
| Con | Confirmation |
| CPCS | Common Part Convergence Sub-Layer |
| CPI | Common Part Identifier |
| CR | Circuit Related |
| CR | Connection Request |
| CR | Call Reference |
| CRC | Cyclic Redundancy Check |
| CS | Capability Set |
| CS | Convergence Sub-Layer |
| CUG | Closed User Group |
| CVI | Circuit Validation Test Indication |
| CVT | Circuit Validation Test |
| DC | Direct... |