Connecting an Analog Phone to an IP Phone System

Using a Cisco SPA112 as an Analog Gateway

Sometimes you need to connect an analog device, whether it's a phone somewhere hard to get an RJ45 Ethernet cable to or perhaps a fax machine. That's when using a VoIP ATA, like the Cisco SPA112, is a good way to proceed. Mount the ATA near your Asterisk server and use the existing phone line (RJ11) to connect with the analog device. Then configure the ATA as an extension in Asterisk. The Cisco SPA112 has two RJ11 analog ports, enough for two devices (or extensions).

The Cisco SPA112 comes reasonably priced and resolves an issue when needing to keep an analog phone or other analog device.

Cisco SPA122 as analog gateway.The Cisco SPA122 offers two analog ports, for two extensions.




Cisco SPA122 ATA showing ports.




Configurations for SPA122 as an analog gateway.

After setting up an extension in Asterisk with name and password, connect the SPA112 ATA administration portal using the Ethernet connection and the default username and password (admin and admin) and start the quick setup wizard. To set up the extension, all you will need is the IP address of your Asterisk server, then save those settings. Out of the box, these ATAs are set to be easily configured using the default settings to set up an analog extension. If you are setting up a fax machine as an extension, assign the DID of the fax machine in Asterisk, forwarded to this extension. Below, we continue for more advanced settings when connecting a fax.

Cisco SPA112 showing ports and connections.



More advanced settings to connect an analog fax machine; see our tutorial at:

Advanced Configurations- SPA112 as a Fax Gateway Device


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