Analog telephony adapter
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Image:Grandstream HT488.jpg Image:IAXy-working.jpg An Analog Telephony Adapter, or ATA, is a device used to connect one or more standard analog telephones to a Voice over IP based network.
[edit] Form
It usually takes the form of a small box with a power adapter, one Ethernet port, and one or more FXS telephone ports. Users can then plug one or more standard analog Telephones into the device and they will operate, usually transparently of the VoIP network.
[edit] Purpose
ATA's are used by many VoIP companies selling a telco-alternative VoIP service, where the device is used to replace a user's connection to an existing telephone company. When sold in connection with a VoIP service like Vonage, the ATA is usually locked so it cannot be used with another company, and the user can only partly change its configuration.
[edit] FXS to Ethernet gateways
The most common ATA box is a device with at least one Foreign eXchange Station (which includes a telephone jack) used to connect a conventional telephone, and an ethernet jack used to connect the adapter to the LAN. Using such an ATA it is possible to connect a conventional telephone to a remote VoIP server. The ATA communicates with the remote VoIP server using a VoIP protocol such as H.323, SIP, MGCP or IAX and encodes and decodes the voice signal using a voice codec such as ulaw, alaw, gsm, ILBC and others. Since ATAs communicate directly with a VoIP server, they do not require any software to be run on a personal computer, such as a softphone.
ATA's generally use the SIP protocol, and are manufactured by many companies including Cisco, Owera, Grandstream, Motorola, Siemens and Sipura.pt:Adaptador para Telefone Analógico de:Analog-Telefon-Adapter pl:Bramka VoIP th:อะนาล็อกเทเลโฟนนีอะแด็ปเตอร์
