Quote Originally Posted by fisamo View Post
The ALG is short for "Application Level Gateway". IIRC, the DLink routers do have one for SIP (which is the one for VoIP that needs to be turned off). Look under your firewall tab. The box on the bottom should NOT be checked. See image below...
Well, the mystery continues. I found the setting and it was checked. I unchecked it and restarted both devices and now there is no dial tone at all. I rechecked the box and restarted, and it's back to the original condition described in the first post. At this point, I am at a loss. Thanks you to everyone for all of the help so far.