If you are in the USA and have AT&T or t mobile (gsm carrier), you can get a Fixed GSM gateway. eBay has them for less than 100.00. It's a small box with a cellular antenna, ac adaptor and has a phone jack on it. You take the sim card from your Cellphone, or from your "add a line" extra Cellphone and insert it into the unit. Now you can plug your home phone into it. It emulates a dial tone just like a landline. We have two of them for two lines and they work great. Just a reminder- I don't know if using these would offend your carrier-don't know why it would, but just keep it on the downlow. I actually have my gsm terminals powering all the jacks in my house. I crimped a short jumper of cat 5 on an rj-11 plug and ran it to my patch panel. Or you can just use a modular cord to a phone. Also if you are in a remote area, higher gain cellular yagi outdoor antennas are available.