We use 128K dial up dual channel ISDN. ISDN, Integrated Services Digital Network is a tariffed service from the phone company. For $50 a month, including all taxes, we get two phone numbers, both of which can carry voice or data. We also pay $25 a month to a separate ISP to connect to the Internet. They are cheaper than the phone company.
The ISDN line connects to our ISDN Terminal Adapter, which routes data traffic, generates our dial tone, rings our phones, and automatically dials voice and data calls. Our computers think they are connected directly to the Internet. Because they are fully digital, ISDN data calls connect in just a few seconds. The Terminal Adapter automatically dials the ISP's ISDN number when any machine on the network sends a packet to the router. Unlike satellite, there is no delay and no bandwidth sharing.
Our data connection, which defaults to the dual channel 128K mode is the rough equivalent of a 150K asynchronous modem, which doesn't exist. Another way to look at it -- we get roughly 3 to 3 1/2 times the speed of most peoples 56K connections. We can make and receive phone calls while on line. The 128K connection automatically switches to 64K while the phone call takes place. It switches back to 128K automatically at the end of the call.
ISDN is cheaper in Tennessee than anywhere else in the US. In any other state, you will pay more.