VoIP

Voice over Internet Protocol (commonly abbreviated VoIP) is a protocol for providing voice services over the internet protocol, from a standard web server to a browser or other client endpoint.

Specifications

SIP

Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, multimedia conferences and even IM, video, games and other rich media services.^[1]

PBX

Private Branch eXchange (PBX) are telephone switches (hardware) and/or call-routing routing applications (software) that run the telecommunications systems (phones and possible mobile/wireless phone calls) of a particular home, business or office, as opposed to one that a common telecommunications carrier or telephone company (TelCo) operates for many businesses in their entire network, or, for the general public as a fee-for-service. PBXs are also referred to as Private Automatic Branch eXchange (PABX) or Electronic Private Automatic Branch eXchange (EPABX) and make connections among the internal telephones of a private network and also connect that network to the broader Public Switched Telephone Network (PSTN) via trunk lines. Because they incorporate telephones, fax machines, modems, and more, the general term "extension" is used to refer to any endpoint on the organization or network's branch. PBXs are differentiated from "key systems" in that users of key systems manually select their own outgoing lines, while PBXs select the outgoing line automatically. Hybrid systems combine features of both.

DID

Direct Inward Dialing Number (commonly abbreviated as DID or DDI) is a solution to the problem most businesses face, when they want to have several incoming telephone numbers used for specific purposes (such as 1-800-323-SALE for the Sales Department and 1-800-323-INFO for general inquiries). DID provides a way to re-use a limited number of physical phone lines to handle calls to different published numbers. In a business with DID, the phone company uses DID signalling to identify the number they are about to connect to the business's PBX. Historically, this was done by pulsing the last 3 or 4 digits of the number being dialed before connecting the number. The PBX would use these DID digits to switch the call to the right recipient. ^[2] In modern PBX's, typically, digital methods (example: PRI) are used to do the same thing, ie. supply the "called party" information.^[3]

VoiceXML

VoiceXML is a standard at the application layer (rather than the network, data or other layer in the protocol stack), and serves the purpose of providing Automatic Speech Recognition (ASR) based on a set of textual commands or action keywords to be listened for/recognized, and, Text-To-Speech (TTS) for synthesis of voice data from textual inputs.

Tools

OpenCNAM: https://www.opencnam.com/ | EXAMPLE - Whitehouse (open source CallerID database)

Softphone

Software TelePhone (commonly abbreviated as Softphone) is a native Mobile Phone client application for connecting to a PBX, or otherwise supporting VoIP calls.