What is a VoIP Gateway?

A VoIP Gateway, or Gateway, is a network device which helps to convert voice and fax calls, in real time, between an and Public Switched Telephone Network (PSTN). It is a high performance gateway designed for Voice over IP applications. Typically, a VoIP gateway comes with the ability to support at least two T1/E1 digital channels. Most VoIP gateways feature at least one and telephone port. Controlling a gateway can be done with the help of the various protocols like MGCP, SIP or LTP.

Benefits of VoIP Gateways

The main advantage of VoIP gateway is that it can provide connection with your existing telephone and fax machines through the traditional telephone networks, PBXs, and key systems. This makes the process of making calls over the IP network familiar to VoIP customers.

VoIP gateways can end a call from the telephone and can provide user admission control using IVR (Interactive Voice Response) system and provide accounting records for the call. Gateways also help direct outbound calls to a specific destination, or can end the call from another gateway and send the call to the PSTN.

VoIP gateways plays a major role in enhancing carrier services and also supports the simplicity of the telephone calls for less cost and easy access. Flexible call integration has been developed at less cost which enables programmable call progress tones and distinctive ring tones.

Functions of VoIP Gateways

The main functions of VoIP gateways include voice and fax compression or decompression, control signaling, call routing, and packetization. VoIP gateways are also power packed with additional features such as interfaces to external controllers like Gatekeepers or Softswitches, network management systems, and billing systems.

Future of VoIP Gateway Technology

Over the years, VoIP gateway has become an efficient and flexible solution and is used for office data and voice connectivity. Besides the connectivity performance, VoIP also offers better reliability under a variety of circumstances.

The future of VoIP gateway is very clear and precise; high-density, scaleable, open platforms need to be designed and implemented to allow the millions of installed telephones and fast-growing number of H.323 computer clients (such as Netscape's Communicator and Microsoft's NetMeeting) to communicate over IP. Many vendors are in the process of designing interoperable VoIP gateways according to the latest architectures to meet the changing demands of service providers, corporate network clients, and individual carriers.

What is an Analog Telephone Adapter?

An Analog Telephone Adapter (ATA), also known as the Analog Telephony Adapter, is an electronic device used to enable one or more analog telephones or facsimile machines for l(VoIP) calls and faxes. An Analog Telephone Adapter basically creates a physical connection by use of telephone and internet cables between a conventional phone or fax and a computer or an gateway. The ATA usually comes with a digital phone and internet plan provider but it can also be bought independently. The Analog Telephone Adapter makes voice calls and faxing over the internet possible without the user needing to upgrade existing traditional telephony systems.

Benefits of Using an Analog Telephone Adapter

Making voice calls and sending faxes over the internet are significantly cheaper than doing so over traditional phone lines. There is no loss of functionality as call forwarding, call conferencing, and other features may still be included in VoIP subscription plans.

The Analog Telephone Adapter allows the user to immediately take advantage of the lesser costs involved in making calls over the internet. It also eliminates the need to get rid of existing phones and replace them with IP specialized phones. Moreover, ATAs are also generally cheaper than specialized digital which are capable of direct USB port or Ethernet gateway connectivity.

FXS to USB Adapters

The first type of Analog Telephone Adapters is called FXS to USB Adapters. FXS stands for Foreign Exchange Station. Such an ATA is a simple device that has one or more RJ-11 jacks or FXS telephone ports. Each phone jack can accommodate a phone or a fax machine. This ATA has an output cable which is in turn plugged into the personal computer's USB port. The computer becomes its means of connecting to the internet.

In this case, the ATA merely makes voice calls over the internet more convenient than using computer speakers and microphone or headsets; it does not directly interact with the VoIP server. The actual analog-to-digital conversion is done by the computer software, generally known as the softphone, which needs to be installed in the computer to which the ATA is connected. This software is supplied by VoIP service providers. This software converts voice data to digital data packets transmittable over the internet.

FXS to Ethernet Gateways

The second type of Analog Telephone Adapters directly performs analog-to-digital voice conversion. As such, Analog Telephone Adapters of this type do not need a softphone for VoIP. It communicates directly with the VoIP server using protocols such as SIP (the most common protocol for ATAs), H.323, IAX or MGCP. Voice signals are encoded and decoded using GSM, A-law, u-law and other such voice codecs.

Physically, an FXS to Ethernet Gateway ATA has one or more standard telephone jacks to which conventional telephony equipment can be plugged in. Analog voice data is converted to digital data and transported through an RJ-45 cable which is connected to the Local Area Network through its direct connection to the Ethernet hub or switch.