6.5.6+Serial+vs.+Parallel+Transmission

= **Needs editing.** = =**__Compare Parallel transmission with Serial transmission__**=


 * __General__**
 * Both Transmissions (Parallel and Serial) are used to connect peripheral devices and enable us to communicate with these devices
 * Since these systems were developed in the 1970s and 1980s these are legacy systems and have been replaced by usually USB


 * __Serial Transmission__**
 * The serial transmission usually consists of 9 pins that connect the data in a series, thats why the name serial port[[image:Serial_port.jpg width="202" height="156" align="RIGHT" caption="A serial Port with 9 pins"]]
 * The port is based on the model of the parallel transmission, however the 9 pin model had taken off before the 25 pin model (parallel transmission) could be implemented in most computers.
 * The serial port is similar to ethernet cables and was therefor used in the 1980s to connect terminals and other devices to the computers
 * The communication the serial transmission only goes over 3 wires
 * The ground signal
 * One wire that sends
 * and one wire that receives
 * This allows communication in both directions at the same time
 * Nowadays the standard speed of serial transmissions is given at 115 KB per second
 * In order to keep the signal from making errors, at the end of every transmission a partly bit is sent
 * A Partly Bit is a bit that is end in he end that is there to make sure that the connection is not faulty
 * If it is sent and return incorrect then the computer knows that there is a error with the connection
 * Due to the simplicity if the connection a shielded connection can be transferred over 75 meters (250 feet), far more than a parallel transmission could.
 * Due to the age serial transmissions are not seen as legacy ports and are not implemented frequently anymore


 * __Parallel Transmission__**
 * The most common type of parallel connector consists of 25 connectors and was implemented in 1970[[image:Parallel_port.jpg width="201" height="106" align="RIGHT" caption="A parallel port with 25 pins"]]
 * There are other types of parallel connectors that use either 36 or 50 pins
 * originally parallel interface only allowed transfer in one direction until the IEEE 1284 standard was created increasing distance and allowing bi-directional transfer
 * Because of the many pins, 8 bits can be transferred at once allowing a much faster transfer of information
 * The 25 connector interface consists of 17 signal lines and 8 ground lines
 * The signal lines are divided into
 * 4 control lines which which are used to initiate the handshaking
 * 5 status lines which are used to communicate the state of the peripheral devices and are used to indicate errors
 * and 8 data lines are used to transfer the data.
 * This interface allows a transfer rate over over 1 MB per second
 * Due to the old age of the parallel port it is now consider a legacy port and is only rarely implemented

Created by: Daniel Gillo Last modification: 13th January 2011

Sources
 * "Parallel Port." Wikipedia, __The Free Encyclopedia.__ 11 January 2011. Wikimedia Foundation. 12 January 2011. __https://secure.wikimedia.org/wikipedia/en/wiki/Parallel_port__
 * "Serielle Schnittstelle." __Wikipedia, The Free Encyclopedia.__ 32 December 2010. Wikimedia Foundation. 12 January 2011. __https://secure.wikimedia.org/wikipedia/de/wiki/Serielle_Schnittstelle__
 * Jones, Richard. __Computer Science Java Enabled__. Victoria: IBID Press, 2004