Computer communications, in the context of this handbook, refer to the exchange of messages and information as well as access to data sources, irrespective of physical distance, using computers and telecommunications devices, such as telephones and modems. Details on the basic equipment requirements and costs for computer communications are given in Sections IV, V and VI.
This handbook does not discuss communications between computers in a single office (also known as Local Area Networks or LANS).
There are three main types of computer communications:
What is electronic mail (e-mail)?Electronic mail, an electronic equivalent of conventional paper mail (often referred to as snail mail), is one of the most frequent applications of computer communications. Using e-mail, people can send messages to one recipient or to several simultaneously. Delivery times range from a few seconds to a few hours, to over a day in some cases, depending on which service is used.
E-mail can be sent extremely cheaply. It can be sent to recipients locally, or to those who have e-mail addresses in other cities and countries.
E-mail is received and sent through an electronic mailbox or e-mail account which is located at a host computer.
A host computer is the computer from which the computer communications service is run. The host computer may also be referred to as a computer network, a bulletin board system (BBS) or an e-mail or on-line service. You connect your computer to your e-mail account at the host computer via a telephone line, as illustrated in the diagram entitled Connecting your Computer to the Host Computer.
Do I have to be connected to the host computer while I write my e-mail?
No. You can either write your e-mail on-line or off-line. The method you use will depend on the services available, and the software supported at the host computer by your e-mail service provider.
What does an e-mail address look like?
As an Internet-style address, it might look like this: sysop@f1.n606.z6.fidonet.org
In fact, a number of networks have address formats which differ from the Internet-style address (although they usually have an Internet-style equivalent). Your service provider can give you further information on how to address your messages, and on what form of address you should give to partners and colleagues who want to communicate with you via e-mail.
On-line use of e-mail means you must be connected interactively to the host computer by telephone line the entire time you are reading new e-mail or while you compose e-mail messages to send out. This way of using e-mail can be quite expensive, since you would spend more time on the telephone than you would by writing your e-mail off-line and then sending it.
Off-line e-mail allows you to write your e-mail messages before you connect to the host computer. Once you have finished writing your e-mail message, you instruct your computer to connect to the host computer. Your messages are then sent out automatically, and the messages waiting for you are automatically received by your computer before it disconnects from the host computer, allowing you to read your newly received e-mail at your leisure. Off-line e-mail lessens the amount of time spent connected to the host computer, and is therefore cheaper and more efficient.
Sending messages off-line is a more viable option in countries where there is only limited and expensive access to telephone lines. But on-line accounts still offer considerable flexibility, since they usually provide other features such as the ability to browse interactively through databases and computer conferences (or bulletin boards), which would not be available on accounts offering only off-line facilities. These features will be discussed in the next section, 'Computer Conferencing and Databases'.
Do some accounts have the option of on-line or off-line e-mail?
Yes. Some services, such as CompuServe and many Fidonet services, offer both kinds of service for the same account, and often provide software which allows for both kinds of use. It should be pointed out that on-line accounts can be used in a variety of ways. For instance, previously saved messages can be sent out once you connect. This saves on the time spent connected to the host computer when using on-line accounts.
Is it possible to send faxes via e-mail and is it cheaper?
Yes. You can send faxes locally, nationally and even internationally if your local service provider has made arrangements with other service providers abroad. Faxes sent via e-mail are not always delivered instantly, however. A fax sent via e-mail can take anywhere from a few hours to one day to reach its destination. It is best to check with your service provider on approximate delivery times.
A fax sent internationally as an e-mail message is cheaper, since you avoid the cost of an international telephone call. The e-mail service near the recipient converts the e-mail message into a fax, and sends it to the recipient at the lower cost of a local call. A few computers in the US even offer free fax services. Ask your network provider for details.
A significant limitation of most existing e-mail systems is their language capability. As discussed elsewhere in this handbook, existing communications software provides only limited support for many languages. This can be a problem when using e-mail for faxing within a country whose language is not well-supported by existing communications software.
Using e-mail to send faxes is almost always cheaper for international communications. But before using this method for domestic communications, you need to carefully consider speed, expense, and language limitations relative to other available means.
How secure or private are e-mail messages?
No communication medium is 100% secure or private. E-mail is no exception. E-mail can be made relatively secure, however, by using such techniques as passwords, encryption programs, and so on).
What is a virus and can it damage my computer?
A virus is a program that can damage your computer system's software and data. Viruses can be accidentally introduced into your system through corrupted programs which have been loaded onto your computer. They can cause your computer to behave erratically or, in some cases, render your entire system useless. Most users exchange only simple text (ASCII), however, which cannot be infected by viruses.
Executable programs (or software) sent by e-mail, on the other hand, can transmit viruses. This is highly unlikely, however, since software made available on computer networks is usually checked thoroughly for viruses by network service providers. If you do want to check for viruses, you must get some virus-scanning software to do so. The virus-scanning procedure ensures that the program does not contain viruses or anything that might damage your computer system. Your local e-mail service provider can be a good source of advice on which virus-scanning software to use, and where to find it.
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