Whoa, when did this thread turn into a Vonage topic?
FAX
I have Vonage and use one line for both voice and fax. Adding a 2nd dedicated Vonage fax line got to be too expensive. The final cost was only a few dollars cheaper than having my Talk America POTS line.
There are a few tricks to get faxing to work....
1) Set your initial connect speed pretty low like 9600 baud. If that doesn't work, go lower. You faxes will take longer to send, but just remember that those minutes are already included in your bill. Even long distance.
2) Do the same with your initial connect speed for receiving. For some reason, I can receive quicker than send.
3) You Voice Mail will not work with FAXing. You need to disable this and use a normal answering machine. The trick here is to record your "Greeting" with about 2-3 seconds of silence at the beginning. This gives your fax (hooked up to the same physical line as the answering machine) a moment to detect if the call is a fax or not. The FAX should be in "Auto" mode.
If anyone needs more tips, let me know. I can go through my menus on the fax machine and see if I set anything else. I fax all the time and maybe 1 wont go through a month. On the second try, it works.
911
Check out your area through Vonage... I live near a major city so I already had E911. Another thing to remember is that even if you cancel your POTS line, by law, they have to keep 911 active on it. So you could have one phone in your house still connected to the POTS line and have it be the cool RED emergency phone used only for 911. And it'll be free!
Outages
Outages are rare and are only because the power has gone out or my internet is down. With Lingo, my service was down all the time! Vonage has been much better. The cool thing, however, is that you can set Vonage up to detect an outage. When it occurs, all calls are forwarded to a 2nd number of your choice. So, when Vonage is down because of power or internet loss, all calls go to my cellphone.
Quality
I used to get an annoying echo problem on Vonage. I could hear myself on the return. I just called Vonage on my cellphone while my wife was making test calls with the Vonage line and they had it fixed in about 15 minutes.
Porting Numbers
I got lucky and was able to port my number. Vonage will port any number they can. It depends on your area and the company that currently "owns" your number. If there are any delays, it's not because of Vonage. When I moved back into my home town, I asked the phone company if the number I grew up with was available. It was! And now, if I move to anywhere else in the US, I can take that number. I'm planning on moving about 20 miles from here and wont need a new area code. It's cool having the number you grew up with. I still get calls for my dad from time to time and it's nice being able to keep my dad's old buddies in touch with him.