The first stage of Internet connectivity that we will consider involves machines which are not directly connected to the Internet. Such machines can still communicate with the Internet through what are called gateways - links capable of passing electronic mail from one system or network to another. The first introduction of many teachers to the national network often comes through systems of this type. We will discuss in the section local bulletin board systems and their big brothers, the commercial operations such as Compuserve, Prodigy and America Online. These systems provide electronic messaging services, typically accessible by dialup over standard voice-grade analog telephone lines. Thousands of such systems exist across the country - some maintained by hobbyists and others operated as small businesses. Individual stand-alone systems are typically established for a single purpose (such as the support of a particular product) or for personal experimentation. Small bulletin board systems can be quite inexpensive to set up, but there is a wide range of services of this type, including the national operations just mentioned, whose users number in the hundreds of thousands.
People desiring to access such systems need to have a computer, a modem and an available telephone line, and must use software to provide the terminal characteristics necessary for the bulletin board system in question. Many such systems are designed to work with simple access terminals, for which there are many commercial and public domain terminal emulation programs available. This allows for the interoperability of many different types of computers which may choose to access these systems.
The price of using a bulletin board system depends on several factors:
Computer. For most bulletin board systems almost any currently-manufactured computer will be adequate. Some systems require specialized software, which may restrict users to a particular class of computers, but typically even this software will run on any Apple Macintosh or on any personal computers which support Microsoft Windows.
Modem. The data rate of a given network link defines the bandwidth of that link. Current modems range in speeds up to 14,400 bits per second (or about 1500 characters per second). The price of these modems in now typically less than $200. Slower modems, with speeds of 2400 bits per second, are priced as low as $50 and are perfectly adequate for most text-based applications. People wishing to scan large volumes of text will find the faster modems much more satisfying, and it is probably worth the investment for anyone buying a new modem.
Software. Most commercial bulletin board services provide the software necessary to use their service as part of their membership package. There is also a wide range of public domain, shareware and commercial applications suitable for this purpose. The public domain offerings may be used for free, while the shareware offerings typically require a registration fee. The functionality required of this software is that it should allow your computer to emulate the functions of some type of computer terminal, so this software is typically described as terminal emulation software.
Membership. Privately-run bulletin boards may be free or may charge a fee for the maintenance of their equipment. Commercial services charge membership fees, typically on the order of $20 a month.
Connect-time charges. This is a function of both your local telephone service and of your bulletin board operator. The bulletin board may charge for connect time or may provide flat rate pricing. Similarly, your phone company may allow for untimed, unmetered calls, or it may charge by the minute for each call. Connection charges may be as low as $1-$10 an hour, but even these fees can add up to huge costs for heavy users of such services.
A difficulty of setting up bulletin board systems has to do with the question of scaling: a system which works well for a handful of users may be unusable for hundreds or thousands of users. An obvious problem has to do with the number of telephone lines provided for dial-in access. This number must be adequate to support all those people wishing to use the bulletin board system simultaneously. And of course the computing power and disk space on the host system must also match the required load.
Bulletin board systems also scale poorly in terms of access. While it might be inexpensive for one person to dial into a remote bulletin board, a school with 200 students seeking access to the same service would find it quite expensive to install 200 telephone lines for this purpose. As we shall see in the sections which follow, there are models of connectivity available to such communities of users which are more powerful and flexible than bulletin board systems and can actually be much less expensive to use.
A bulletin board system which exists in complete isolation from other computer networks is obviously a limited resource. This fact has not deterred many commercial operators from establishing services of this type. Not surprisingly, these isolated services have not been too successful in commercial terms (except where they seek to serve a very narrow range of interests), and such systems are tending to become more of a rarity. The largest such effort, Prodigy, has recently provided its users with electronic mail access to the Internet.
The sections which follow will describe stages of connectivity which can reach more services than are available to a simple bulletin board system. We will see that there is a wide and growing range of services available only at these higher stages of connectivity.