MODEM AND SECURITY MONITORING

MODEM

A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves. A modem converts between these two forms.

Fortunately, there is one standard interface for connecting external modems to computers called RS-232. Consequently, any external modem can be attached to any computer that has an RS-232 port, which almost all personal computers have. There are also modems that come as an expansion board that you can insert into a vacant expansion slot. These are sometimes called on board or internal modems.

While the modem interfaces are standardized, a number of different protocols for formatting data to be transmitted over telephone lines exist. Some, like CCITT V.34, are official standards, while others have been developed by private companies. Most modems have built-in support for the more common protocols -- at slow data transmission speeds at least, most modems can communicate with each other. At high transmission speeds, however, the protocols are less standardized.

Aside from the transmission protocols that they support, the following characteristics distinguish one modem from another:

bps : How fast the modem can transmit and receive data. At slow rates, modems are measured in terms of baud rates. The slowest rate is 300 baud (about 25 cps). At higher speeds, modems are measured in terms of bits per second (bps). The fastest modems run at 57,600 bps, although they can achieve even higher data transfer rates by compressing the data. Obviously, the faster the transmission rate, the faster you can send and receive data. Note, however, that you cannot receive data any faster than it is being sent. If, for example, the device sending data to your computer is sending it at 2,400 bps, you must receive it at 2,400 bps. It does not always pay, therefore, to have a very fast modem. In addition, some telephone lines are unable to transmit data reliably at very high rates.

voice/data: Many modems support a switch to change between voice and data modes. In data mode, the modem acts like a regular modem. In voice mode, the modem acts like a regular telephone. Modems that support a voice/data switch have a built-in loudspeaker and microphone for voice communication.

auto-answer :An auto-answer modem enables your computer to receive calls in your absence. This is only necessary if you are offering some type of computer service that people can call in to use.

data compression :Some modems perform data compression, which enables them to send data at faster rates. However, the modem at the receiving end must be able to decompress the data using the same compression technique.

flash memory : Some modems come with flash memory rather than conventional ROM, which means that the communications protocol scan be easily updated if necessary.

Fax capability: Most modern modems are fax modems, which means that they can send and receive faxes.

SECURITY MONITOR

• Computer security is to protect data, manage Internet usage, and simplify IT systems management. It enables organizations to avoid costly loss of data leaks, regulate users' Internet and PC activity, and effectively manage IT systems. 

To ensure that all files are sent and received free from any form of threat security, antivirus and filter malicious codes should be updated from time to time.

Data and network to be controlled from: 

Performance invalid ~ control can be done using verification (authentication) as the user identification code  / password and encryption 
The virus' code introduced illegally can destroy the system. Data & network should be protected from viruses by using hardware and software specifically designed for the purpose. (Firewall) 
~ Disaster Data & network should be preserved from disasters such as theft, fire, earthquake, flood and other. Maintenance are also can be done by performing a backup.

Authentication 

Verify the sender of a message.

It verifies the identity of the user who will reach the resources that are available in data communication .
Authentication can be done using the password. Says - password 
Form of security that is often used .
It is required by the host computer or certain devices to verify identity before entering the system.

There are three methods of authentication using the password :

Something owned ( Something Possessed )
An inherent ( Something embodied )
An unknown ( Something known ) .

Password

• Check the identity of a computer system in 2 ways.
• password

Something that belonged to the identification scheme .

• Example : password ( pin number ) used in conjunction with an ATM card or a smart card.

Password 

• Something embodied Involved the examination of the users to the unique characteristics found on a user .
• This procedure is ideal for tight security system where threats to the system can cause severe consequences because the cost is high.
• Example: voice recognition , finger print, the pattern of eyes / retinal pattern, and a digital signature.

Password ~ something known

• In this method , by asking for a password , the computer system will also ask questions related to the agent ( user) .
• Example: questions such as date of birth, mother's maiden name , identity card number and others.

Types of Password

• Password issued by the user ~ users to create their own password .
• Password issued by the computer  ~ computer produces a random password .
• Tunable password ' compromise between password issued by the user and the computer. Computer users have a password and use it to create a new password etc.