Jan 05, 2015 Serial vs Parallel Transmission The primary difference between serial and parallel transmission is in the way the data is transmitted. In serial transmission it is sequential whereas, in parallel transmission, it its simultaneous. In the computer world, data is transmitted digitally using bits. In serial transmission, data is sent sequentially where one bit after the other is sent through a single wire. In this transmission one bit flows at one clock pulse. In Serial Transmission, 8 bits are transferred at a time having a start and stop bit. Parallel Transmission: In Parallel Transmission, many bits are flow together simultaneously from one computer to another computer. Parallel Transmission is faster than serial transmission to transmit the.
Active4 years, 4 months ago
- Parallel Transmission Vs Serial Transmission Oil
- Serial And Parallel Transmission
- Parallel Transmission Vs Serial Transmission Test
- Parallel Transmission Vs Serial Transmission Diagram
- Serial Data Transmission Vs Parallel Data Transmission
- Examples Of Parallel Data Transmission
Intuitively, you would think that parallel data transmission should be faster than serial data transmission; in parallel you are transferring many bits at the same time, whereas in serial you are doing one bit at a time.
So what makes SATA interfaces faster than PATA, PCI-e devices faster than PCI, and serial ports faster than parallel?
Hennes
60.1k7 gold badges94 silver badges143 bronze badges
modestmodest
8062 gold badges9 silver badges13 bronze badges
5 Answers
You cannot formulate it this way.
Serial transmission is slower than parallel transmission given the same signal frequency. With a parallel transmission you can transfer one word per cycle (e.g. 1 byte = 8 bits) but with a serial transmission only a fraction of it (e.g. 1 bit).
The reason modern devices use serial transmission is the following:
-
You cannot increase the signal frequency for a parallel transmission without limit, because, by design, all signals from the transmitter need to arrive at the receiver at the same time. This cannot be guaranteed for high frequencies, as you cannot guarantee that the signal transit time is equal for all signal lines (think of different paths on the mainboard). The higher the frequency, the more tiny differences matter. Hence the receiver has to wait until all signal lines are settled -- obviously, waiting lowers the transfer rate.
-
Another good point (from this post) is that one needs to consider crosstalk with parallel signal lines. The higher the frequency, the more pronounced crosstalk gets and with it the higher the probability of a corrupted word and the need to retransmit it.1
So, even if you transfer less data per cycle with a serial transmission, you can go to much higher frequencies which results in a higher net transfer rate.
1 This also explains why UDMA-Cables (Parallel ATA with increased transfer speed) had twice as many wires as pins. Every second wire was grounded to reduce crosstalk.
terdon
43.6k11 gold badges98 silver badges147 bronze badges
mpympy
19.8k4 gold badges57 silver badges76 bronze badges
Htc mobile unlock software free download. The problem is synchronization.
When you send in parallel you must measure all of the lines at the exact same moment, as you go faster the size of the window for that moment gets smaller and smaller, eventually it can get so small that some of the wires may still be stabilizing while others are finished before you ran out of time.
By sending in serial you no longer need to worry about all of the lines stabilizing, just one line. And it is more cost efficient to make one line stabilize 10 times faster than to add 10 lines at the same speed.
Some things like PCI Express do the best of both worlds, they do a parallel set of serial connections (the 16x port on your motherboard has 16 serial connections). By doing that each line does not need to be in perfect sync with the other lines, just as long as the controller at the other end can reorder the 'packets' of data as they come in using the correct order.
The How Stuff Works page for PCI-Express does a very good explination in depth on how PCI Express in serial can be faster than PCI or PCI-X in parallel.
TL;DR Version: It is easier to make a single connection go 16 times faster than 8 connections go 2 times faster once you get to very high frequencies.
![Parallel transmission serial transmission Parallel transmission serial transmission](https://www.mbaknol.com/wp-content/uploads/2016/02/parallel-serial-transmission-mbaknol.png)
28.4k6 gold badges84 silver badges102 bronze badges
Parallel Transmission Vs Serial Transmission Oil
Parallel isn't inherently slower, but it does introduce challenges what serial communication does not.
But many of the fastest links are still parallel: The front-side bus in your computer is typically highly-parallel, and is usually among the fastest interlinks in a computer. Fiber optic connections can also be highly-parallel by carrying multiple wavelengths over a single fiber. This is expensive and therefore not typical, though. The most common form of Gigabit ethernet is actually 4 parallel channels of 250Mbit Ethernet in a single wire.
The most pronounced challenge introduced by parallelism is 'crosstalk': when signal current starts or stops, it momentarily induces a small current on the wires next to it. The faster the signal, the more often this happens, and the more difficult it gets to filter out. Parallel IDE attempted to minimize this problem by doubling the amount of wires in the ribbon cable, and connecting every other wire to ground. But that solution only gets you so far. Long cables, folds and loops, and proximity to other ribbon cables all make this an unreliable solution for very high-speed signals.
But if you go with only one signal line, well then you're free to switch it as fast as your hardware will allow. It also solves subtle synchronization issues with some signals travelling faster than others.
Serial And Parallel Transmission
Two wires is always theoretically twice as fast as one, but each signal line you add subtly complicates the physics, which may be better to avoid.
tylerltylerl
1,9841 gold badge14 silver badges21 bronze badges
Serial data transmission isn't faster than parallel. Fbi voluntary appeal file application. It's more convenient and so development has gone into making fast external serial interfacing between equipment units. Nobody wants to deal with ribbon cables that have 50 or more conductors.
Between chips on a circuit board, a serial protocol like I2C that needs only two wires is much easier to deal with than routing numerous parallel traces.
But there are plenty of examples inside your computer where parallelism is used to massively increase the bandwidth. For instance, words are not read one bit at a time from memory. And in fact, caches are refilled in large blocks. Raster displays are another example: parallel access to multiple memory banks to get the pixels faster, in parallel. Memory bandwith depends critically on parallelism.
Creative media player 5 download. This DAC device touted by Tektronix as 'the world’s fastest commercially available 10-bit high speed DAC' makes heavy use of parallelism to bring in the data, which comes into the DAC over 320 lines, which are reduced to 10 through two stages of multiplexing driven by different divisions of the master 12 GHZ clock.If the world's fastest 10 bit DAC could be made using a single serial input line, then it probably would.
KazKaz
2,1821 gold badge12 silver badges21 bronze badges
Parallel Transmission Vs Serial Transmission Test
Parallel was the obvious way to increase speed when logic gates were slow enough that you could use similar electrical techniques for buses/cables and on-chip transmission. If you're already toggling the wire as fast as your transistor allows, so the only way to scale is using more wires.
With time, Moore's law outpaced the electromagnetic constrains so transmissions over cables, or even on-board buses, became a bottleneck compared to on-chip speeds. OTOH, the speed disparity allows sophisticated processing at the ends to use the channel more effectively.
-
Once propogation delay approaches the order of a few clocks, you start worrying about analogue effects like reflections => you need matched impedances along the way (especially tricky for connectors) and prefer point-to-point wires over multi-point buses. That's why SCSI needed termination, and that's why USB needs hubs instead of simple splitters.
-
At higher speeds you have multiple bits in flight at any given moment along the wire => you need to use pipelined protocols (which is why Intel's FSB protocols became frightfully complicated; I think packetized protocols like PCIe were a reaction to this complexity).Another effect is a multi-cycle penalty for switching the direction of signal flow—that's why Firewire and SATA and PCIe using dedicated wires per direction outperformed USB 2.0.
-
Induced noise, aka crosstalk, goes up with frequency. The single biggest advance in speeds came from adoption of differential signalling which dramatically reduced crosstalk (mathematically, an unbalanced charge's field goes down as R^2, but a dipole's field goes down as R^3).I think this is what caused the 'serial is faster that parallel' impression — the jump was so large that you could go down to 1 or 2 differential pairs and still be faster than LPT or IDE cables. There was also a crosstalk win from having only one signal pair in the cable, but that's minor.
-
Wire propogation delay varies (both because wire lengths are hard to match across 90º turns, connectors etc. and because of parasitic effects from other conductors) which made synchronization an issue.The solution was to have tunable delays at every receiver, and tune them at startup and/or continually from the data itself. Encoding the data to avoid streaks of 0s or 1s incurs a small overhead but has electric benefits (avoids DC drift, controls spectrum) and most importantly allows dropping the clock wire(s) altogether (which isn't a big deal on top of 40 signals but is a huge deal for a serial cable to have 1 or 2 pairs instead of 2 or 3).
Note that we are throwing parallelism at the bottleneck — today's BGA chips have hundreds or thousands of pins, PCBs have more and more layers. Compare this to old 40-pin microcontrollers and 2 layer PCBs..
Most of the above techniques became indispensable for both parallel and serial transmission. It's just that the longer the wires, the more attractive it becomes to push higher rates through fewer wires.
a CVn
25.1k9 gold badges79 silver badges128 bronze badges
Beni Cherniavsky-PaskinBeni Cherniavsky-Paskin
protected by bwDracoJun 12 '15 at 14:55
Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?
Would you like to answer one of these unanswered questions instead?
Not the answer you're looking for? Browse other questions tagged data-transfer or ask your own question.
Parallel Ports
Parallel Transmission Vs Serial Transmission Diagram
Of the two, the parallel port is the older port design with the first use in the early 1970s, allowing printers to be hooked directly into a mainframe and print orders carried out by entering a section of code through the command station. The parallel port allows for a one-way transmission of data from the source to a secondary device, such as a printer. In some circles, the parallel port became commonly known as the printer port, since that function was originally the most common application of the device. Early external modems and storage devices are a couple examples of the broader use of parallel ports. Since the beginning of the 21st century, the parallel port has largely been replaced by the USB port, although some ancillary devices still allow for connection by both means.
Serial Data Transmission Vs Parallel Data Transmission
Parallel ports generally have a minimum of 25 pin connectors that make up the actual connecting part of the device. These 25 pins will match up with the end of the device that the port is being connected to and it is through the pins that information is transferred. Each pin connector performs a different function.
Serial Ports
One key difference between a serial and parallel port is that the serial port allows for data to be transferred to the hard drive from a remote device or transferred from the hard drive to a remote device, as opposed to the parallel port's outbound-only communication; a serial port can also be referred to as a communication port or bi-directional port. This two-way communication process makes it possible to connect work stations to larger terminals as well as a wide range of peripheral devices such as external hard drives or smart phones. Serial ports are known to be slower than parallel ports, however, because they can transfer information in two directions simultaneously.
Examples Of Parallel Data Transmission
A serial port will usually be made up of either nine or 25 pin connectors; several of the connectors in a 25 pin port are not used regularly. Originally, a nine pin port was believed to be more compact and cost-effective, but often it was not efficient enough to serve its purpose.