ISDN
ISDN is a service that operates at 128 Kbps and is available from your phone company. Charges for ISDN connections usually resemble those for analog lines—you pay per call and/or per minute, usually depending on distance. ISDN charges also can be flat rate if linked to a local Centrex system. Technically, ISDN consists of two 64-Kbps channels that work separately. Load-balancing or “bonding” of the two channels into a 128-K single channel is possible when you have compatible hardware on each end of a connection (for instance, between two of your campuses). What’s more, as a digital service, ISDN is not subject to the “line noise” that slows most analog connections, and thus offers actual throughput much closer to its promised maximum rate. You can make ISDN connections either with an ISDNready router or with an ISDN terminal adapter (also called an ISDN modem) connected to the serial port of your router. Again, modems are best for single users, because each device needs its own...