F
- Failback
- Failover
- Fallback
- Fault Tolerance
- Fax over IP (FoIP)
- Fax Server
- Feature Access Code (FAC)
- Feature Code
- Federation
- Fiber Optic
- Field Replaceable Unit (FRU)
- Find Me/Follow Me
- Firewall
- Firmware
- Firmware Update
- Flash Hook
- Forced Disconnect
- Foreign Exchange Office (FXO)
- Foreign Exchange Station (FXS)
- Forward Error Correction (FEC)
- Forwarding (Inoltro)
- Frame Relay
- Fraud Detection
- Frequency Division Multiplexing (FDM)
- Full Duplex
- Function Key (Tasto Funzione)
