Like the nuclear power industry that promised electricity so cheap they wouldn't even have to meter it, the predictions are overly optimistic. Because of the differences in facilities and tariffs across the country, some technologies that work well in some communities may not be feasible for others. Most people still connect by dialing into a network node using a standard phone line and analog modem. This table illustrates the different data rates that may result from the use of the various technologies listed above, but the speed of the connection doesn't tell the entire story. Data rate may change while a call is in progress, or from call to call.
Modems typically fall back to fastest speed they can connect at reliably for the given conditions.
Cheapest access, available nationwide. Can aggregate multiple channels for higher speeds. Transmit and receive data rates are symmetric. Many inexpensive ISDN adapters are available for serial ports or a network connection. ISDN is prohibitively expensive in some parts of the country, but is very cheap in Illinois.