The convergence of computer and communications has had a profound influence on the way computer systems are organized. 

Computer based communications – through E-mail, bulletin board services (BBS), computer conferencing, networking and on-line database etc.-offer independent sectors, academic and small institutions, particularly in developing countries, a modern, effective and affordable communication tool kit with which to share information, network, conduct research and support awareness programmes on a wide array of subjects. 

Computer communications in this context, 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. 

Electronic mail, popularly known as E-mail is one of the most frequent applications of computer based communications which has revolutionised the way in which message is delivered from one place to the other.  Whether it is used to communicate within a work group (where most communication occurs) across an organisation or externally with customers, suppliers, peer groups or competitions, e-mail transforms the nature of human interaction. 

At present there are more than 20 million people in the world who use E-mail for their day-to-day work.  Ease of use coupled with accuracy and speed of message delivery systems have contributed most to the success of E-mail.  An E-mail message can be compared with a postal message.  It consists of a header with important information like the addresses of the originator and the recipient(s), date and time of the message and subject etc. and a message body which is usually in a text format.  Optionally, there could be enclosures with a message.  Using e-mail, people can send messages to one or more recipients simultaneously.  Delivery times range from a few seconds to a few hours, to over a day in some cases, depending on which services is used. 

Electronic mail works on a store and forward principle.  When a user prepares a message and submits it for transmission, it is received by the local message transfer agent.  If the E-mail address is correct then the user’s job is over.  The message header is analysed by special software which is analysed by pecial software which is available with the message transfer agent to identify the recipient and his location.  If the recipient is a local user then the message is delivered to his In-Mail-box, otherwise, it is forwarded (posted) to remote E-mail system (node).  The remote node repeats the same process until the message is delivered to recipient’s mail box.  At any stage if the recipient’s address is found to be incorrect an error message is returned to the sender with or without the original message. 

E-mail is quite cheap compared to other modes of communications such as conventional mail, telex, telegram, Fax etc.  It can be sent to recipients locally or to those who have E-mail address in other cities and countries.  Text based material such as simple messages, letter, notes, memos, unformatted conference papers, documents, formatted text ie. any document transmit other information like executable files and data files as e-mail attachments.

For those who have used a good e-mail system, the benefits are quite apparent, if often difficult to quantify.  E-mail saves time for those who use it through reduction of interruptions, delays, unproductive overheads in face-to-face meetings and the myriad of unproductive material associated with paper-based communication systems.  E-mail improves the quality of communication through speeding up organistional communication, creating permanent searchable communication, and forcing brevity, clarity and precision.  It has been instrumental instrengthening interpersonal relationships making it easier to communicate and resolve problems. 

Online Vs Off-line E-mail

Online use of e-mail means you must be connected interactively to the host computer by telephone line the entire time you are reading 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 most of the time on the telephone than you would be 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 you 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 reduces the amount of connected time to the host computer and is therefore cheaper and more efficient.

Sending messages off-line is  more viable in countries where there is only limited acess to telephone line.

Overview of X.400 architecture

Today many E-mail systems are switching over to X.400 convention.  X.400 is the common standard recommended by CCITT (International Telegraph and Telephone Consultative Committee) for structuring and transmitting e-mail messages.

The basic activity performed by Message Handling System MHS is the conveyance of electronic messages through a communication system.  The users of this service are primarily individuals who wish to exchange interpersonal messages, but the medium may also be used for other such applications as event-logging or to transmit EDI messages.

A simple MHS model is shown in fig.  This model outlines the basic components involved in transfer of a message from one user, the sender, to another user, the recipient.  The orginator makes use of a User Agent (UA) to compose a message and submit it to the Message Transfer System  (MTS). A user agent is similarly involved when the MTS delivers message to its recipient. After delivery, the recipient will process the received message using services of his user agent.  Within the MTS, a set of MTA’s cooperate in conveying messages to their intended recipients, together, the collecting of UA’s and MTA’s comprise the message handling system (MHS).

The key feature of MHS is that it  operates in a store and forward manner.  This implies that the originator of a message need not bother about whether a recipient is ready to receive  a message or not.  Instead, the originator can submit a message convenient to him and equally the recipient can choose the time when he will actually read it.  Another important provision of MHS is the ability to send message to many recipients.

Over view of DAINET

For the past one year Development Alternatives is providing E-mail and electronic conferencing facility to some Independent sector organizations as part of our project DAINET.  The MTS of Development Alternatives consists of a 24 hour dedicated server installed with the operating system LINUX which is a clone of the UNIX  operating system available freely on internet.  The server with the help of a modem and telephone  line is connected to Ernet (Educational and Research network provided by Department of Electronics) which is acting as the Internet  gateway for DAINET.  The Donationrs of this system are supplied with the shareware version of Waffle  and Pegasus mail.  The users should have a non-dedicated telephone line, modem and a computer to use our system.  The users read and write E-mails in Pegasus mail and after that connecting to the server for the transfer of e-mails is performed by Waffle.  The LINUX server connects with the main server in Ernet several times in a day for the mail transfer.

However, an important new trend  emerging is to integrate e-mail application with other software programs, i.e. e-mail can be not only between person to person, but both person to application and application to person.  While the integration of e-mail with other applications will be a long process, there are already numerous success stories.  Clearly e-mail is emerging as one of the backbone technologies transcending the barriers  of time, distance and political boundaries  which has witnessed relentless expansion of Internet thereby bringing us closer to the global community.

 

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