Help installing a Grandstream GXW4104 & GXW4004

Here is the situation, I got a standard analog phone line here at the office that I use for incoming calls, and what I want to do is extend that line through the internet so I can make and receive calls from that line at my home.

At the office I got (2) T1 Lines, and at the home I got Comcast Cable Internet.

I can get into the configuration screens on both routers, but I have no idea on how to properly set them up. The company I bought these units from does not offer any tech or paid tech support and grandstream will not return my phone calls and emails.

Is this even possible and how would I go about setting it up?

BTW, I did manage to download the instructions on the internet from Grandstream, but I cannot make heads or tales from it