One question that always comes up is whether a single ISDN line is
sufficient to support multiple users. After all, many individual telecommuters
have a dedicated ISDN line. The answer is yes, with some minor caveats. An ISDN
line will easily support half a dozen active users. Six active users typically
means 50 people who use the Internet for email, Web browsing, and occasional
file downloading. Most users notice better performance when they use an ISDN
line instead of an analog modem connection with lower throughput, only when
multiple users are simultaneously downloading large amounts of data, such as
transferring files from an FTP site or viewing Web pages with many images.
Using Microsoft's Proxy Server with a high-speed modem or ISDN adapter is a
low-cost, high-performance alternative to more expensive dedicated lines. ISDN
has the advantage of providing faster connect times and faster throughput than
analog modems. Proxy Server makes the connection transparent to network users so
the network appears to have a dedicated connection to the Internet. A transient
connection can further reduce expenses by letting you use a lower cost dynamic
IP account. Most ISPs have dynamic IP accounts for analog modems in the range of
$20 to $40 per month. ISDN accounts are $10 to $20 more expensive but still much
less expensive than fixed IP accounts that typically run $250 or more per month.