I'm trying to follow the direction in "Configuring the Cisco SPA8800 IP Telephony Gateway in an Asterisk Environment" to set up the system, except that I don't configure the FXS ports since we don't have analog phones connecting to SPA 8800. The call from PSTN to SIP phones works fine, but I can not make call from SIP phones to PSTN. The SIP log on Asterisk server shows Asterisk sent INVITE to SPA 8800 but got a 404 Not Found response. However, there is nothing in SPA 8800's syslog for the call, so I have no idea why 8800 rejected it. The attached image shows the part of line configuration.
The document does not include an example calling from SIP phone behind Asterisk to PSTN line, is that supported? Without using FXS ports, how to make SIP calls to PSTN?
Any help on this will be much appreciated.
