Analog Telephone Adapter (ATA) Setup

An ATA (Analog Telephone Adapter) converts a traditional analog telephone or fax machine to work with a VoIP system. This allows businesses to reuse existing phones during a VoIP transition or maintain analog devices like elevator phones and fax machines. Popular ATAs: Grandstream HT801/HT802, Cisco SPA112, Obihai OBi202. Connect the ATA to the network via ethernet, and the analog device to the ATA's FXS port (Phone 1 or Phone 2). Access the ATA's web interface via its IP address. Configuration: enter the SIP proxy address (your VoIP server), SIP port, extension number, and password. Set the codec to G.711 PCMU/PCMA for best quality. For fax machines, set the T.38 options as described in the FoIP article. After registration, you should get a dial tone on the analog phone. Common issues: analog phone ringtone differs from expectations (adjust ring voltage/frequency in ATA settings), voice quality issues (enable echo cancellation, check jitter buffer settings).