Introduction
The USB standard is the most widely used for the connection of devices varied to the computer, but the industry also been giving great prominence to the technology, FireWire (or IEEE 1394 or, still, i. LINK). But, what is FireWire? What this technology has as a differential? Who is behind of your development? How it works the FireWire? What are the benefits in relation to its main competitor, the standard USB? Is that and a bit more you will see in this article.
What is FireWire?
FireWire it is a technology that enables connection and communication at high speed of several devices among themselves, especially between a computer and one or more compatible devices. Behind its development is none other than the Apple (though other entities and companies have participated in its creation), that has worked on this technology during the 1990s. In 1995, the technology received the standardization IEEE 1394 reason which some manufacturers use that name instead FireWire, since the latter name is, in fact, registered by Apple. In this context, it is important to note that Sony, one of the first companies (besides Apple itself) using this technology, is called i. LINK.
The FireWire was created having as a goal to achieve a number of objectives, how to: allow a quick and easy connection of multiple devices, to allow a transmission rate of data is high and stable, be cost feasible to manufacture, work as a “plug-and-play” (that is, the instrument must work as soon as plugged in) and allow the transmission of data and the power supply are made by the same cable.
It is known that Apple computers are very used in applications that involve both video and audio. Works of this kind usually make use of several gigabytes. It is because of this that the default FireWire “served as a glove” to Apple users, because if, for example, a cameraman need to spend for your iMac an the film made in your digital camcorder, you can do this quickly using a connection for FireWire. The industry soon realized this advantage, and that is why today it is possible to find computers and other devices of various brands with this technology. In the beginning, only few companies were part of this list, between they are: JVC, Matsushita (Panasonic), Canon, Kodak and the already mentioned Sony.
The following image shows a Apple computer Mac Pro G5 with entries FireWire 400 and FireWire 800:
Characteristics of FireWire
The technology, FireWire has more than one version, but the first, also known as “FireWire 400” or “IEEE 1394a”, already impressed by its features:
– Data transmission speed of 400 Mb/s (approximately 50 MB per second);
– Speed flexible: possibility of work in three speeds: 100 Mb/s (S100), 200 Mb/s (S200), and 400 Mb/s (S400);
– Ability to work with up to 63 devices at the same time;
– Immediate recognition of the device by the operating system after your connection (plug-and-play);
– “Hot pluggable”, that is, a device can be connected or disconnected at any time, without the need to turn it off;
– The connections can count on up to 45 Watt of power;
– full functioning with connection cables of up to 4.5 meters.
Just for comparative purposes, the technology USB 1.1 works with a data transmission rate of 12 Mb/s (equivalent to 1.5 MB per second). Because of this, the USB has received a “upgrade” that made it a little higher than the FireWire 400: USB 2.0, whose transmission rate is 480 Mb/s. But it didn’t take very long for the standard FireWire also received a new version: in 2002, the market met the “FireWire 800” (or the “IEEE 1394b”), whose main features are:
– Data transmission speed of 800 Mb/s (twice the standard earlier);
– Compatibility with connection cables of up to 100 meters;
– Compatibility with devices that use the FireWire bus to 400 (in practice, this feature may depend on the equipment).
Worth mentioning that, in addition to the FireWire count with versions IEEE 1394a and IEEE 1394b, there is also a released version prior to these: the original version (IEEE 1394-1995) which, after some changes in its specifications, became a in what is known today as IEEE 1394a. Note that you may find with great frequency of this name in the compatible devices with the technology now that Apple owns rights in the designation FireWire, as I have already informed before.
The operation of the FireWire
In essence, the technology, FireWire is a bus transmission of data type serial. When a device is connected to the other using this technology (for example, when an external HD is connected to the input FireWire from a computer) or when it is necessary the connection of two bus bars, the connection is established by a circuit usually called “ponte” (bridge). When this occurs, the transmission data can be made two-way, that is, both the devices can send and receive information by the same connection. In the case of FireWire 400, the data transmission it is done by an encoding scheme called Data/Strobe (D/S) while FireWire 800 incorporates the name encoding 8B10B. This last schema can make that there is less distortion in the signal transmission, therefore, so that there is less the loss of data. This is one of the features that help the FireWire 800 to have almost double the speed of standard previous.
The transmission of data through technology FireWire also account with an interesting feature: an operation mode “isochronous”. In practice, this means that it is possible to transmit data from one device to another in real time, without influence any mechanism that delays significantly the transmission. This functionality is especially attractive for use in cameras digital video or external hard Drives, for example, once users these devices can work with large volume of data without losing a lot of time.
In the connections, FireWire is not mandatory to have a “device hub” for all devices involved if you “see”. The own bus makes each a if to see each other, even when there are more than two in a same connection. This, incidentally, has a “schema tree”, that is, the devices are connected to one another by hierarchies. For this to occur, it is necessary that one of the devices has an identification code (ID) that indicate as being the main, the “root node”. From there, the remaining devices will be receiving IDs lower. Via rule, the farther away is the device from the root node, the more low is your ID.
You can say that this ID is, basically, divided in two parts: ID and physical ID of the bus. The ID of the physical, usually composed 6-bit, distinguishes one node of the connection (that is, a device) within a bus. The second ID, in turn, distinguishes the bus, and is composed of 10 bits.
Connectors and cables FireWire
The cable that allows the connection of devices to a FireWire interface 400 is composed of up to 6 copies (or 6 small wires built-in). Of these, two routes are used for the power supply electric, while the other – separated in pairs – treat specifically, the transmission and synchronism of data. Note that some cables may contain 4 lanes instead of 6. In this case, the wireless transmission of energy does not exist.
In the case of FireWire 800, the cable can contain up to 9 lanes. Of the three way additional, the two serve to reinforce the protection of the cable, so that it does not receive or emit interference. The third way additional had no function specific up until the time that this article was made available in AbbreviationFinder.
The images below show the connectors and the FireWire inputs that are the standard of the market. Note that it is possible to find cables with connectors 9-way at one end and 4 or 6 way on the other. Thus, FireWire devices 400 can be used in devices with FireWire 800, when there is compatibility.
Ending
The standard FireWire is a technology that is stable, efficient and that offers advantages that make it arguably superior to the bus USB. But because this latter is still more popular? The reasons are complex and varied, but can be summarized to the following: the implementation of FireWire is a bit more expensive that of the USB standard, not only for the technical part, but also by issues involving patents and “royalties”. There have been several discussions to define how much the industry would have to pay to the companies directly involved with the development technology (especially Apple), which has made many companies preferred to give support to the USB 2.0 standard. But this is changing. Although it is unlikely that the standard FireWire to overcome the USB technology, its use has been increasing considerably.
In the near future, we can count with even more news about the technology FireWire: although there is still no much information available, everything indicates that the industry is already working on a new version of this bus.
