A data stream is an information sequence being sent between two devices. Data streams exist in many types of modern electronics, such as computers, televisions and cell phones. A typical data stream is made up of many small packets or pulses. Each of these packets or pulses contains a small amount of information. When combined together, they make up the full piece of information sent. The process of sending these signals is called data transmission.
There are many different aspects of data transmission that affect the final method used to create a data stream. One of the most basic classifications is serial and parallel transmission. In a serial transmission, the data stream is sent in its entirety along a single cable. At the endpoint, the data is collected and reassembled. There is rarely any difficulty with this method, as all of the packets should arrive in the order in which they were sent.
A parallel data stream is sent along multiple paths to the same destination. This is typically used in a larger network to avoid creating bottlenecks where too much information is coming through a single location. With this method, it is possible for the information to arrive out of order due to differences in hardware hops and transmission distance. This can occasionally cause data corruption if sequences are reassembled out of order.
Data may exist in either asynchronous or synchronous streams. In a typical asynchronous stream, a special character is put at the beginning and end of the data packet. These special characters, called start and stop bits, tell the receiving computer when a specific data piece begins and ends and aids in the reconstruction of the data after it comes in.
Synchronous data streams don’t have the start and stop bits—they rely on clock time instead. The internal clocks for the two devices are synchronized, and information sent between them is stamped with the clock time. Using this method, the receiving device can just reassemble the information chronologically. Problems can crop up using this method when the two computers don’t maintain synchronicity; packets may be reassembled incorrectly or possibly thrown out entirely.
Monitoring data streams is important for security reasons. As data moves through a network, it is possible for individuals to intercept the packets. Using specialized analyzers, people can open the packets and locate information that they are not supposed to have. Certain encoding techniques make this difficult to do in some cases, but unsecured information transmission should be kept to a minimum.