I finally figured out the ATA's admin password and am writing this while connected to its LAN port.
It agrees with the Comcast modem/router that its IP address is 10.0.0.5 and obviously it's got internet access, since I'm writing this. Meanwhile the red status light is still blinking (I've now got a phone plugged in, though my experience is that it's not a factor for the statuslight). No dial tone.
I'm stumped, Comcast says they block nothing (confirmed here), and Primus says Comcast sometimes does, but DMZ and PF didn't fix it.
Any other suggestions most welcome, we can get Xfinity Voice for $20/mo but that's $20 more than we wanted to ;pay, and it allmakes me nervous for when we return home.
Webber's occasional bargain blog: www.wwwebber.com