What Is the Function of a VoIP Gateway?

 The set sights on and perform of a VoIP Gateway is to designate an interface in the middle of the avowed telephone networks using digital TDM (Time Division Multiplexing) technology and that of IP Networks expected to carry IP packets containing digital speech. The VoIP Gateway has to translate the digital media format used going on the subject of for the local network and the PSTN (Public Switched Telephone Network) in both directions. In accumulation, the Gateway will plus have to translate along in the middle of the every second signalling protocols used concerning the local network and PSTN.

Today's Voice again IP networks digitise analogue speech for telephone calls my means of a Codec which stands for Coder Decoder or Compressor De-compressor. There are a number of codecs used within VoIP systems, subsequent to the most common of these sentient thing ITU-T codecs G.711 and G.729, and the GSM codecs used within the mobile telephone networks. Two versions of the g.711 codec are used within the avowed digital telephone networks which are based largely around 64Kbps digital telephone channels. The digital telephone channels are multiplexed together using a method referred to as Time Division Multiplexing to form either T1 or E1 lines. A T1 parentage is intended to carry 24 digital telephone calls, whereas an E1 stock is intended to carry 30 digital telephone calls. These multiplexed trunk lines are used to interconnect exchanges and as well as secure a customary PBX (Private Branch Exchange) to a Telephone Operator's row.

A VoIP Gateway will dependence to retain a number of codecs, consequently as to be clever to translate in the middle of the digital codec formats used by the PSTN and the VoIP enabled Local Area Network.

In add-on to translating digital voice formats, the gateway must with be dexterous to translate surrounded by exchange signalling formats. The Public Switched Telephone Network uses two main forms of signalling which are referred to as CAS (Channel Associated Signalling) and CCS (Common Channel Signalling). The former is used re the analogue telephone extraction together in the midst of the telephone fan and the disagreement by passing telephone dialling codes often by means of audio tones, and this method is known as DTMF (Dual Tone Multi Frequency). Pulse dialling is furthermore used in some systems. Common Channel Signalling is used along in the midst of exchanges and gateways to appendix telephone signalling recommendation within the wider telephone network.

SIP (Session Information Protocol) has evolved as the dominant signalling protocol within VoIP Systems, and has largely replaced the cumbersome ITU signalling protocol H.323. SIP is a easy client / server protocol that is used to setup, go without and teardown VoIP telephone calls. MGCP (Media Gateway Control Protocol) is used by some Voice on top of IP systems to run the behavior of a VoIP Gateway and Cisco uses SCCP (Skinny Call Control Protocol) upon some older systems as a means of communicating together in the middle of the settle users and the Cisco Callmanager call run agent.

Signalling System 7 is the CCS system used within all the Public Telephone Networks, including home-based and mobile systems. In fact, it is sometimes referred to as the "Glue" that connections every share of Public networks together and allows us to make calls together amongst Mobile phones, home-based phones and VoIP phones.

Other main functions and features of VoIP Gateways postscript:

Fax as nimbly as voice compression and decompression

Packetising digital voice information

Control signalling

Call Routing

Interface to added outside devices such as SoftSwitches and H.323 Gatekeepers

Gateways supplied by oscillate vendors are often packed as well as proprietary features as dexterously as the pleasing features conventional of a VoIP Gateway. Selecting the right one for your organisation or situation requires cautious thought and some research.

A to your liking little matter VoIP Gateway is Cisco's SPA3102 which provides a single FXS (Foreign Exchange Service) RJ-11 connector, enabling the fan to be unventilated to a single going on to conventional telephone or FAX robot upon the local network side, and a single FXO (Foreign Exchange Office) harbor to enable membership to the local Telco. Two adding together Fast Ethernet ports manage to pay for relationship to the home or office Local Area Network. An added Fast Ethernet harbor provides a connection to a broadband modem or router.

For more info VoIP Gateway.

For auxiliary little situation faculty, Cisco's VGA204 Analogue Voice Gateway provides 4 x FXS RJ-11 ports to let connectivity for 4 telephones or fax machines and 2 Fast Ethernet network ports. It supports every one the major network signalling standards such as SIP, SCCP, MGCP and H.323v4.

VoIP Gateways are continuing to elaborate as enhancements to existing protocols continue and optional appendage VoIP protocols are being developed. All the major Gateway vendors are bothersome to profit a larger flavor part and therefore proprietary features are something to see out for, particularly in the little event freshen. Check out your options back jumping in and buying the first Gateway and be sure of your ultimate requirements.