Cisco SPA2102-SF Administration Guide - Page 93

Configuring the PSTN (FXO) Gateway on the SPA3102 How VoIP-To-PSTN Calls Work 6 - FXO Port: The SPA3102 has 1 FXO port that you can connect to the PSTN. Configure the FXO settings by using the SPA3102 PSTN Line page. • The SPA8800 is designed to work with your PBX as a PSTN gateway and a VoIP gateway. Call control is provided by a standard PBX, an Asteriskbased IP PBX, the SPA9000 Voice System, or an Internet-based call control system. - FXS Port: The SPA8800 has 4 FXS ports that you can connect to standard analog telephones or fax machines. Configure the FXS settings by using the SPA8800 Phone 1-4 pages. - FXO Port: The SPA8800 has 4 FXO port sthat you can connect to the PSTN. Configure the FXO settings by using the SPA8800 Line 1-4 pages. How VoIP-To-PSTN Calls Work To obtain PSTN services through the SPA3102 or the SPA8800, the VoIP caller establishes a connection with the PSTN Line by way of a standard SIP INVITE request addressed to the PSTN Line. One-Stage Dialing (SPA3102 and SPA8800) One-stage dialing allows a call to be started over VoIP and then immediately get a dial tone on the PSTN. When you take a phone off hook and dial a number, the call is automatically routed to the VoIP or the PSTN, based on the dial plan. On the SPA3102, you can enable HTTP Digest Authentication. In this case, the SPA3102 challenges the INVITE with a 401 response if it does not have a valid Authorization header. The Authorization header should include a parameter, where n refers to one of eight VoIP user accounts that can be configured on the ATA device. The credentials are computed based on the corresponding password using Message Digest 5 (MD5). The parameter must match one of the VoIP accounts stored on the ATA device. You can configure these settings on the Voice tab > PSTN Line page. For more information, see "VoIP Users and Passwords (HTTP Authentication) section," on page 212. Cisco Small Business ATA Administration Guide 93