A local area network(LAN) can provide communication services on single site. However, the power of computer communications lies in the use of wide area network(WAN). A large company may have its own private WAN for security reasons. Most organisations and individuals rely on the internet, a global WAN consisting of many interconnected networks, containing servers.
A server is a combination of computer and software that provides a service to other client computers or application programs. Everyone has heard of the internet and most of us have used it at one time or another time. Once you have paid an Internet services provider (ISP) for internet access, most communication services are available at no extra charge.
Most people`s first experience of using a service provided over the internet is using a web browser to view information from a web server, but it is important to understand that the World Wide Web(WWW or Web) is just one of many Internet services. Each website consists of collection of information stored as HTML or similar files, known as web pages.
These files and related graphics, sound and video files are stored within a single directory(or folder) an web server with an Internet address known as its Uniform Resource Locator (URL), such as http://www.google.mn.
Communication programs
pFax
pTelephony
pVoice over Internet Protocol
pVideo-conferencing
pEmail
pInstant messaging
Fax
Fax is a pre-computer technology for sending images of documents over telephone lines. It has been successfully adapted for use by computers.
Features of fax programs include:
pSending a scanned image of printed documents over a phone line to recipient with a fax machine or suitably equipped computers
pSending an image of electronic file, usually by ‘printing’ the file with the fax program`s virtual printer, or ‘ printer driver’
pReceiving a transmitted fax and displaying or printed it.
Telephony
The receptionist in a small organisation can use a switchboard program with a headset onsisting of headphones and microphone to answer conventional phone calls and transfer them to colleagues. Call management software performs a similar function in a multi-agent call centre and has management functions for monitoring performance
Voice over internet Protocol
Voice Internet Protocol (VoIP) technology enables calls to take place over the internet rather than over communication circuits maintained by telephone companies. VoIP providers offer use of their VoIP servers and free VoIP software to allow users make free VoIP-to VoIP calls using a microphone and loudspeakers or headphones. Video-conferencing
Many organisation use video-phone calls as a cheap method of video-conferencing, in which several participants in different locations can have a discussion and see each other at the same time. Imagine of flying all the participants to one place for a meeting they can stay where they are and hold a meeting electronically. This is save the time, monetary and environmental costs of travelling to meetings and accommodating people in hotels.
Many people first use electronic message or email through a web application, such as Hotmail or Yahoo mail, known as ‘webmail’. Often, they do not realise that email is an Internet service provided by mail servers, not web services.
Many people, especially at work, use an email client program such as Microsoft Outlook to communicate directly with their email server, without using a web browser programs. One of the advantages of doing so is that the user can compose messages with the full editing facilities of a word processor.
Features of email client programs include:
pTransmission of typed messages and attached files anywhere in the world to recipient with an email address
pStorage of names and email address of contacts in an ‘ address book’ or ‘ contact list’ (the user can select an address from the address book or from a list of matching addresses that appears as they start to type the name or address
pCreation of an ‘address group’ ( or ‘ distribution list’), which is a list of email addresses of contact to whom the user wants to send the same messages
pSending a message simultaneously to one or more individuals or groups; this can be done by entering all email addresses into the ‘To’ field, or the ‘Cc’ or ‘Bcc’ fields. ‘Cc’ means ‘ carbon copy’ and all recipients can see who else the message has been sent to. ‘Bcc’ means ‘blind carbon copy’ and none of the other recipients can see the email addresses in this field.
pSending a message with a ‘digital signature ’; this is a cryptographic technique to ensure that the message comes from the true sender and has not been altered
pSending a message with encryption, to prevent anyone but the intended recipient receiving it.
pSending a message by using a Reply button, correctly addressed and includes a copy of the original message.
Instant messaging
Instant messaging (IM) is a service provided by an instant messaging server, although the user`s application program may be a web applications. Features of instant messaging programs include:
pSending type messages between users whenever a character is typed or the Enter/Return is pressed, depending on the application
pDisplay of the availability or other status of contacts on a contact list
pMultiple, simultaneous, two way conversations;
pGroup conversations
pOptional telephony and video
pExport of conversation as a text file
People use IM programs and web applications on a similar range of devices and for similar purposes as email. The major difference is that even with only text, users have more sense of a conversation, because they perceive communication as being instant or in ‘real-time’.
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