- a
- ACD
- Acoustic Echo
- Analog Phone
- ANI
- API
- Asterisk
- ATA
- Attenuation
- Auto Attendant
- b
- B-Channel
- Backbone
- Bandwidth
- Barge
- Baud
- BLI
- BRI
- BYOD
- c
- Cable Internet
- Call Analytics
- Call Center
- Call Hunting
- Call Logs
- Call-Monitoring
- Call Queue
- Call Recording
- CAT5/CAT5E/CAT6
- CDR
- Central Office
- Centrex
- CLEC
- Cloud
- Cloud Communications
- Cloud PBX
- Codec
- Conference Bridge
- Conferencing
- Contact Center
- Corporate Directory on Phone
- CPE
- CRM
- CSR
- CSU/DSU
- CTI
- Custom Greetings
- Custom Hold Music
- Custom Messages
- Custom Schedules
- d
- D-Channel
- Data Center
- Data Transfer Rate
- Demarc
- DHCP
- Dial By Extension
- Dial By Name
- Dial-By-Name-Directory
- Dial Plan
- Dial Plan Editor
- DID
- Digital Phone
- Direct Outward Dialing
- DNS
- DS0
- DSL/ADSL
- DTMF
- Duration
- Dynamic IP Address
- e
- E-911
- E Carrier System
- E1
- Echo Cancellation
- Escape from call queue
- Ethernet
- Exchange Area
- Extension Dialing
- Extensions
- f
- Fax to Email
- Find Me/Follow Me
- FiOS
- Firm Order Commitment FOC
- g
- G711 Codec
- G729 Codec
- Gateway
- h
- Hosted
- Hosted VoIP
- Hotspots
- Hunt Group
- Hybrid-Hosted
- i
- IAD
- IAX Trunk
- ILEC
- Inbound Call Filters
- Individual Call Logs
- Intercom
- International Calling
- IP
- IP Address
- IP Phone
- ISDN
- ISP
- ITSP
- IVR
- IXC
- j
- Jitter
- k
- Kbps
- l
- LAN
- Last Number Redial
- LATA
- Latency
- LDAP
- LDAP Integration
- LEC
- Legacy
- LERG
- Line Failover
- LNP
- LOA
- Local Directory on Phone
- Local & Long Distance Dial Tone
- Login/Logout
- m
- MAC
- MAN
- Mbit
- Mean Opinion Score (MOS)
- Message Waiting Indicator
- Mobility
- Modem
- MPLS
- MTA
- n
- NANP
- NAT
- Network Closet
- o
- On-Premises vs Cloud
- Online User Portal
- p
- Packet
- Packet Loss
- Packet Switching
- Paging
- Paperless Fax
- PBX
- Ping
- PoE
- POP
- Porting Numbers
- POTS
- Presence Monitoring
- PRI
- Private IP Address
- Provisioning
- PSTN
- Public IP Address
- q
- QoS Quality of Service
- Queue Call Barge
- Queue Call Recording
- Queue Call Spy
- Queue Call Whisper
- r
- Rate Center
- Redundancy
- Report Caller Hold Time
- Ring Groups
- RJ9
- RJ11
- RJ45
- Router
- RTP
- s
- Server
- Service Uptime
- SIP
- SIP Trunk
- SIP Trunking
- Softphone
- Softphone Client
- Speed Dial
- Spy
- SRTP
- Static IP Address
- Switch
- t
- T.38
- T-Carrier System
- T1
- TCP
- Toll-Free Number
- u
- UCaaS
- UC&C
- UDP
- Unified Communications
- Unified Messaging
- UPS
- v
- Video Conference
- Virtual Number
- Virtual PBX
- Voicemail
- Voicemail to Email
- VoIP
- VPN
- VSFTP
- w
- WAN
- Web Conference
- WebRTC
- Whisper
- WiFi
- WLAN