VoIP phone

IP PhoneIP PhonesEthernet-based phoneIPIP desktop phoneIP telephoneIP telephonesphoneVoIPVoIP phone service
A VoIP phone or IP phone uses voice over IP technologies for placing and transmitting telephone calls over an IP network, such as the Internet, instead of the traditional public switched telephone network (PSTN).wikipedia
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Voice over IP

VoIPvoice over Internet Protocolvoice-over-IP
A VoIP phone or IP phone uses voice over IP technologies for placing and transmitting telephone calls over an IP network, such as the Internet, instead of the traditional public switched telephone network (PSTN). VoIP phones can be simple software-based softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone. Various schemes exist to allow one Internet telephony user to talk to another entirely via Internet and without incurring the cost of a PSTN call. Some are based on SIP addresses, some on proprietary protocol such as webcam or Internet chat applications. While it's not uncommon for two clients of the same voice over IP provider to talk to each other online for free, the various Internet telephony applications often do not talk directly to each other - requiring calls be gated to PSTN and back at full toll rates.
In addition to VoIP phones, VoIP is also available on many personal computers and other Internet access devices.

Session Initiation Protocol

SIPSession Initiation Protocol (SIP)SIP Trunking
Digital IP-based telephone service uses control protocols such as the Session Initiation Protocol (SIP), Skinny Client Control Protocol (SCCP) or various other proprietary protocols.
A SIP phone is an IP phone that implements client and server functions of a SIP user agent and provides the traditional call functions of a telephone, such as dial, answer, reject, call hold, and call transfer.

Power over Ethernet

PoE802.3at802.3af
Power source - a battery or DC/AC source; some VoIP phones receive electricity from Power over Ethernet
This allows a single cable to provide both data connection and electric power to devices such as wireless access points, IP cameras, and VoIP phones.

Softphone

soft phonePC-to-PC calling
VoIP phones can be simple software-based softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone.
VoIP phone

SIP URI scheme

Various schemes exist to allow one Internet telephony user to talk to another entirely via Internet and without incurring the cost of a PSTN call. Some are based on SIP addresses, some on proprietary protocol such as webcam or Internet chat applications. While it's not uncommon for two clients of the same voice over IP provider to talk to each other online for free, the various Internet telephony applications often do not talk directly to each other - requiring calls be gated to PSTN and back at full toll rates.
As the client may be a SIP phone or other device with just a numeric, telephone-like keypad, various schemes exist to associate an entirely numeric identifier to a publicly reachable SIP address.

Caller ID spoofing

spoofspoofeda false origin is displayed
Caller ID display
If the caller name is sent with the call (instead of being generated from the number by a database lookup at destination) it may be configured as part of the settings on a client-owned analog telephone adapter or SIP phone.

Telephone

phonetelephonesLocal Telephone Service
VoIP phones can be simple software-based softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone.
The customer equipment may be an analog telephone adapter (ATA) which interfaces a conventional analog telephone to the IP networking equipment, or it may be an IP Phone that has the networking and interface technology built into the desk-top set and provides the traditional, familiar parts of a telephone, the handset, the dial or keypad, and a ringer in a package that usually resembles a standard telephone set.

Voice engine

A voice engine or a digital signal processor (DSP) to process RTP messages. Some IC manufacturers provides GPP and DSP in single chip
Voice engines handle the voice processing for an IP Phone system on a standard processor, compared to prior generations of systems which required dedicated, math-optimized digital signal processor chips.

Mobile phone

cell phonemobilemobile phones
There are several Wi-Fi enabled mobile phones and PDAs that have pre-installed SIP client software, or are capable of running IP telephony clients, including most smartphones.
VoIP phone

Extension Mobility

Accounts are usually set and memorized on the phone itself. A more sophisticated feature is dynamic download of account settings, also known as "extension mobility". This feature allows settings stored on a server to be downloaded to the phone, based on user login. The user logs into the phone and that phone becomes the user's extension. This feature requires both a client (phone) and a server, usually in the context of unif ied communications systems.
The Cisco Extension Mobility feature, sometimes referred to as hoteling, allows a user to temporarily configure another IP telephone as his own.

Comparison of VoIP software

proprietary formatsSIP Softphones
Softphones are client devices for making and receiving voice and video calls over the IP network with the standard functions of most original telephones and usually allow integration with VoIP phones and USB phones instead of using a computer's microphone and speakers (or headset).

Invoxia

Invoxia Triby
Invoxia designs and markets smart office phones which communicate with smartphones and hybrid consumer IP Phone and wireless speakers.

List of utility cooperatives

Magic Valley Electric Coop
JANIS is a DSL broadband, cable tv and IP Phone provider, run by (Wikipedia Japanese: Nagano Cooperative Computing), a subsidiary of Japan Agricultural Cooperatives (JA). Despite the name, it sells to individuals and organisations.

Communications in Japan

Communications in Japan § Telephone servicescommunicationsJapanese telephone company
IP phone lines in use: 16.766 million (2007)

Brastel Telecom

Recently they have started to invest in IP phone technology through their FLiP and Basix services.

Web-based VoIP

integrated into a web page
Instead of using dedicated, hard-ware based VoIP devices, such as IP phones, analog telephone adapters, or integrated VoIP/Internet access routers, services are provided via a web page and the facilities of the user's computer or hand-held device for accessing and operating a locally attached head set, and microphone.

VzRoom

vzRoom is a software system developed by Manipeer Limited for multi-party video conferencing, media sharing and VoIP phone integration.

Sipgate

Customers were expected to use a client software or a SIP-compliant hardware (a VoIP phone or ATA) to access its services.

BroadVoice

Customers can make and receive phone calls using an ordinary telephone, IP phone, Softphone or an Android or iPhone cell phone via an application.

Softswitch

soft switchesVoIP softswitch
Although the term softswitch technically refers to any such device, it is more conventionally applied to a device that handles IP-to-IP phone calls, while the phrase "access server" or "media gateway" is used to refer to devices that either originate or terminate traditional "land line" (hard wired) phone calls.

Simple Network Management Protocol

SNMPSNMP management systemSNMP Trap
Sometimes called network elements, the managed devices can be any type of device, including, but not limited to, routers, access servers, switches, cable modems, bridges, hubs, IP telephones, IP video cameras, computer hosts, and printers.

Home network

smart appliancehome networkinghome area network
A network device might require a non-standard port feature such as power over Ethernet (PoE). (IP cameras and IP phones)

VoIP vulnerabilities

Hardphones (a.k.a. VoIP phone) are smart devices, they are more a computer than a phone, and as such they need to be well configured.

Selsius Systems

Selsius designed an IP PBX system consisting of a line of IP phones, a server-based call control application - the Selsius-CallManager, a line of voice over IP gateways and voice applications including voicemail, an automated attendant console and a softphone.