VoIP Phone
A VoIP Phone is a telephone that supports calls over the Internet. VoIP phones are specifically designed for Voice over IP, and are becoming increasingly popular with the adoption of VoIP technology. The devices look similar to standard telephones; however, they often have an LCD display and a menu which allows the user to manage and utilize certain features and settings. VoIP phones allow for users to use Voice over IP technology without the need for a computer. VoIP phones work by converting standard telephone audio signals into a digital format which can be transferred over the Internet and sent to other phones. When a call comes in, a VoIP phone takes the incoming digital signal and transforms it into standard audio.
VoIP phones are different from analogue phones, which do not utilize VoIP and run over the Public Switch Telephone Network, and cell phones, which utilize wireless technologies such as PCS, GSM, CDMA and TDMA. There are some VoIP phones which offer wireless capabilities, like the Cisco WIP310, however, this is an emerging technology for VoIP phones. VoIP phones are commonly referred to in the industry as the EDGE.
VoIP Phone Service
VoIP Phone Service is the networking, connections, data storage, security, software offerings and updates, and customer support needed to support calls over the Internet. VoIP phone service facilitates the connection of VoIP phone calls from the VoIP phone or The Enterprise Border Element (EDGE), to the Public Switched Telephone Network (PSTN), to the Internet Telephony Service Provider (ITSP) and back. VoIP phone service plays a large role in your call quality and feature offering. Most hosted VoIP PBX services offer each of these services while IP-PBX services require you maintain the equipment yourself.
PSTN
The Public Switched Telephone Network (PSTN) is the common telephone network available to the public in the United States. The network was originally completely analog but today it is being transformed into a digital network supporting everything from mobile to fixed telephones.
SIP Trunking
SIP Trunking is a service offered by an Internet Telephony Service Provider (ITSP) that converges voice and data onto one communication line, providing seamless access between the Internet and the worldwide Public-Switched Telephone Network. SIP Trunking routes and transfers voice and data from the Public Switched Telephone Network to a PBX. SIP Trunking works by having SIP protocols direct calls as they travel between the PBX and Public Switched Telephone Network.
There are four components necessary to successfully deploy SIP trunking: a PBX with a SIP-enabled trunk side, an Enterprise Border Element (EDGE) understanding SIP, an Internet Telephony or SIP trunking service provider, and the Public Switched Telephone Network.
ITSP
An Internet Telephony Service Provider (ITSP) offers Internet data service for making telephone calls using Voice over IP technology. Many hosted VoIP PBX providers are also Internet Telephony Service Providers (ITSP). However, plans and service do differ.
Internet Telephony Service Providers (ITSP) supply connectivity to the Public Switched Telephone Network for communication with mobile and fixed phones. SIP trunking is an action taken by the Internet Telephony Service Provider which allows for the connectivity between the Public-Switched Telephone Network and the EDGE.