I am providing this update to my review by using the "comment" feature instead of using the "review update" procedure because I want to include some images, and the review process does not seem to allow that.
I was recently able to start using my 16/3 Comcast Business Class connection for sending and receiving faxes using the Vonage VoIP service (I can even do both at the same time). I did this by replacing the SMCD3G-CCR gateway device with a Motorola SB6121 modem, and adding a ZyXEL GS105S gigabit switch with advanced priority based QoS.
Shown below is a screen capture of a Comcast speed test that was done while I was simultaneously sending and receiving a multi-page high resolution graphic fax.
Shown below is the page that was being both sent and received during the above test (and this image is the received page...not bad for a fax):
Shown below is a graphic diagram of my current network:
If anyone else is having problems with VoIP quality (voice or fax) from a VoIP provider other than Comcast's CDV, I recommend that you try using either a ZyXEL GS105S or GS108S switch with your VoIP ATA connected to the green High-Priority port (although it might not help as much if you have a WiFi router or cable gateway in front of the switch if your gateway/router does not also have a good QoS implementation).
Link to the GS105S product page: »www.zyxel.com/products_services/···html?t=p
Link to the GS108S product page: »www.zyxel.com/products_services/···html?t=p--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.