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Configure a SIP adapter

SIP Analog telephone adapter (ATA)

First of all is important to understand the difefrence between a FXS and FXO port.
To this purpose read this pdf file


Once realized this difference, your work is pretty finished.

The most common analog telephone adapter is a device with at least one telephone jack (FXS port) 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  SIP,  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.

In general SIP ATA are very easy to configure (almost all have a good and simple web interface).

I suggest:

A good SIP ATA with FXS ports is Linsys PAP2
A good SIP ATA with FXS and FXO ports is Linksys SPA 3102

You can find many infos about these two products on

Average price 80 eur

Alfredo Pagano 2007/03/27