High-quality patch cables play an immense role within networks; only through them can fast and smooth data traffic take place. Even in times of wireless transmission technology, a professional network cannot do without the appropriate patch cable. In contrast to radio connections, shielded LAN connections conduct electrical signals much more efficiently, without interference and faster, and they are secure against eavesdropping.
When buying a network cable, however, you should pay close attention to which patch cable you are investing in, because the wrong choice can have a decisive effect on the performance of the network. There are many different types of cables of different qualities, mostly gray in color,available on the market and in stock – these different types can be identified based on certain characteristics.
Requirements for a network cable
First and foremost, a good network cable should be able to transmit data quickly and reliably, but at the same time be robust against interference. Different cables can be used depending on the requirements and intended use. Before buying, there are some criteria to examine:
Cable category (CAT)
Plugs and contacts
Not all network cables are the same; different types with different characteristics are available. They are divided into different categories (Cat). These describe the respective performance. To see how fast a patch cable can transfer data, you should look at the transfer rate. Patch cables of higher categories have the scope of performance of the lower categories per se and expand them with additional properties.
(Standard) patch cable (also straight-through cable or LAN cable)
The patch cable connects a computer with the network distributor (hub, switch or router) and sends data using copper wires. In addition, optical patch cables, so-called LWL, are also available; these work with glass fibers or plastic fibers. The copper network cables have certain characteristics with regard to their design: eight flexible copper wires (each 0.4 to 0.5 mm thick) run parallel to each other under a jacket. Simple copper cables are flexible and can therefore be laid easily; they are also relatively inexpensive. The common type of copper-bound patch cable is the twisted pair cable. It forms the basis for setting up a network.
Twisted pair cable
With this special patch cord, or “copper cable with twisted wires”, four differently twisted wire pairs run inside the plastic jacket. Streams of data flow through each pair. The advantages of this twisting within the patch cables are that they are better protected from external disturbing influences (for example electrical voltage fields from power cables) by twisting them in pairs.
Crossover cable (also called cross-wired cable)
In the case of a crossover cable, on the other hand, two pairs of wires cross. This type of Ethernet cable can be used to connect two PCs without an intermediate router or switch. There are also crossover couplers that connect two standard network cables to serve the same purpose without switches.
These patch cables are particularly suitable for long-term installation behind walls or in cable tunnels. Installation cables have a thicker cable width and more stable plastic insulation; the cable cores are also slightly wider at 0.5 to 0.7 millimeters. Due to their low attenuation, installation cables also pass on their signals via further connections or with increasing length with relatively little loss of quality. Installation cables are therefore perfect for setting up an office network facility or for long-term installation of network infrastructure.
Y-cable as a splitter
The Y-cable can only be described as a cable in the broadest sense, because it actually represents an adapter. This serves to split the network or Ethernet into two parts, which enables two computers to share a cable together be able. This halves the installation effort, but so does the transmission speed when used in parallel.
Categorization of network cables: Cat 1 to Cat 7
The categories of network cables are broken down from Cat 1 to Cat 7. Depending on the patch cable category, increasing speeds can be achieved. The network cable categories one and two do not play any role in network technology today, categories three and four likewise. However, these types of patch cords can still be found very occasionally in old installations. Standard networks are no longer set up with Cat 1-4. For the network structure and the network cabling, Cat5, Cat5e, Cat 6 and Cat7 patch cables are used.
Cat 1,2 and 3
These categories no longer play a role nowadays, the Cat 1 cables (operating frequency up to 100 kHz) could only be used for the transmission of voice. The Cat 2 cables (up to 1500 kHz operating frequency) were mainly used for cabling with ISDN primary rate connection. Cat 3 network cables work with an operating frequency of up to 16 Mhz. These are unshielded twisted pair cables and were standard in America for a long time. The Cat 4 cables supported frequencies of up to 20 MHz, and they too were only found in the USA. Nowadays, the cable categories Cat 5, Cat 6 and Cat 7 can be used to set up a network.
Cat 5 / Cat5e
Cat 5 patch cables are a common standard and are mostly used to set up networks. You can achieve higher data transmission rates in a frequency range of 100 Mhz, the standard designation of these cables is EIA / TIA-568. The Cat 5 cable can transfer data at higher speeds of 100 Mbit / s. Cat5e forms a sub-category, the e stands for “enhanced”. The cable is suitable for Gigabit Ethernet networks with longer cable runs. The Cat 5 cables are suitable for Fast or Gigabit Ethernet.
Another common standard is the Fast Cat5e network cable. The maximum performance is also one gigabit per second, due to the 350 Mhz transmission frequency, the effective speed is even higher than that of the Cat5e cables. The Cat 5 cables are generally a bit more sensitive and have the disadvantage that the attenuation increases quickly. Both types of cable Cat5 and Cat5e are well suited for shorter distances of around ten meters.
Cables in this category are designed for higher frequencies of up to 250 MHz. However, the data transfer rate for data transfers decreases the longer the Ethernet cable is. These cables are used for all voice and data transmissions as well as on ATM and multimedia networks. The cables in the Cat 6a sub-category work with operating frequencies of up to 500 MHz and are particularly powerful. They are suitable for 10 Gigabit Ethernet. As already mentioned, category 5 and 6 network cables are limited to a length of around 100 meters. If this mark is exceeded, the transfer rates decrease. The Cat 6 cables are less sensitive than the Cat 5 and offer higher transfer volumes.
Cat 7 is a standard category whose technology is used worldwide, apart from the USA. This cable class is often referred to as “Class F”, and operating frequencies of 600 MegaHertz are possible with Cat7 patch cables. Cat7 and Cat 7 also have a sub-category, Cat 7a (also class FA), with which frequencies of 1000 MHz and 100 Gbit / s can be achieved. The Cat7 cables all have 4 individually shielded wire pairs in the middle of a common shield.
Attach a patch box
Quality degradation due to external disruptive factors
The quality of a network cable has an exorbitantly high influence on the stability of the network (LAN). A failure due to the nature of patch cables has incalculable consequences for company networks. Cable length, shielding and processing play an essential role in ensuring trouble-free network operation.
Cable length correlates with the transfer rate
All three common standards have one thing in common: the cable length of the patch cable is limited to 100 meters. However, a few other factors also play a significant role here, including damping. If this internal resistance has high values, the maximum length is shortened due to the drop in performance. Power lines running next to the network cable can also disrupt data traffic. It should be noted that the speed and transmission quality of network cables increase due to low attenuation and high signal levels.
Shielding of the patch cables
Correct shielding of a cable also tries to reduce external interference factors. This is particularly important when setting up a network. Patch cables without shielding are called U / UTP (Unscreened Unshielded Twisted Pair). These network cables without shielding are insulated with plastic and can therefore be laid in a flexible and adaptable manner. Since these patch cables do not have any shielding, the transmission quality of these cables is particularly dependent on their length. An unshielded cable should not be longer than ten meters, otherwise the quality will drop rapidly and the patch cable without shielding should not be directly next to power cables.
S / UTP (Screened Unshielded Twisted Pair) describes the simple shielding of a patch cable. In contrast to the unshielded patch cable, there are copper braids or aluminum foils (so-called PiMf) under the outer plastic jacket, which are intended to protect the cable from external interference. However, the higher tolerance of this shielding towards interference has a disadvantage: the patch cable becomes stiff and therefore less flexible. FTP cables (foiled twisted pair) also offer an equally important alternative in which – in contrast to S / UTP – the respective wire pairs are protected. Both ftp and utp form the simplest form of shielding for patch cables, but better than an unshielded network cable or a patch cable without shielding.
A network cable is particularly immune to interference as soon as it is double-sheathed or has double shielding. A cable with such a sheathing is called S / STP (Screened Shielded Twisted Pair) or S / FTP (sftp = Screened Foiled Twisted Pair). With these stp or sftp cables, all cores are individually protected by copper braids or aluminum foils (so-called PiMf).
Plugs and contacts
The shielding of a network cable makes a significant contribution to the quality of the data transmission, and the plugs and contacts are equally important. The Ethernet cables have RJ45 plugs and are equipped with a barb, which should prevent them from drifting out of the socket. However, this barb of the RJ45 connector does not necessarily cover all error scenarios, so you should pay attention to a clean and solid processing in order to keep the wear as low as possible. There are three different processing qualities:
The easily processed and inexpensive patch cables are often titled with the addition “assembled”. Such an RJ45 cable connector offers quite good anchoring, but can still be damaged if it is bent or is plugged in and unplugged very frequently. Special protective caps on the RJ45 plugs can help the simply processed plugs to be more stable and to protect them from dust and dirt even afterwards.
Network cable with kink protection
If the word “booted” occurs in the name of the patch cable, this means that the cable can have a kink protection. A special rubber coating on the connector is used here, which protects the first half a centimeter of the cable against bending. The stability of the network is thus increased, since it is less likely that connectors are damaged by being pulled out quickly.
With this type of cable, the cable and connector merge into one. The plastic housing of the Ethernet cable completely surrounds the connector, so it no longer has any edges and is optimally protected against any breaks or unintentional pulling out.
Optical patch cords
With the help of optical network cables one tries to cover longer distances with a slight loss of quality. However, these optical cables are incompatible with general routers, network cards and other network standards. The optical network cable does not rely on cables made of copper, but works with fiber optic cables (LWL). Optical fiber optic patch cords made of glass or plastic offer several advantages over those made of copper. These fiber optic patch cables can cope better with interference and can be located right next to power cables in the cable tunnel. They are also immune to power fluctuations, and they can even withstand lightning strikes. The fiber optic patch cables are thin, flexible and robust, have a very clear data transmission and are more secure against eavesdropping.
Fiber optic cables and patch cords made from plastic fibers
Optical network cables or patch cables with plastic fibers (also called “POF”) have a price advantage, but this is reflected in the lower quality compared to optical fiber optic cables. The optical fiber optic cables generally have the advantage of lower attenuation and can therefore bridge longer connections without interference thanks to the fiber optic structure.
Optical cables are robust, but due to the technology on which they are based, they must not be bent or kinked. Mixed cables made of plastic fibers and glass fiber are also available, these often have a good price-performance ratio. The already mentioned incompatibility with common, standardized network technology requires special network cards or switches, otherwise converters. These then act as an intermediary between the optical and the copper patch cords.
When buying network cables, you should ask yourself which distances should be overcome and at what speed without interference. When choosing the right cable, you shouldn’t skimp in favor of cheap solutions, but should seriously think in advance about whether the cable can meet your own requirements and the respective purpose. Large company networks in particular need to be well planned with regard to the use of the corresponding network technology. For example, shielding is therefore mandatory. If wrong decisions are made here, this will have a long-term negative effect on the network structure.