Cable types and connectors
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Maitre'D POS
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It is important to be familiar with the various types of cables and connectors that can be encountered in most hardware installations. Here is a list of all the cables and connectors in use today:
Serial cables and connectors are commonly used to connect serial printers, room charge servers and other devices to Maitre’D Back-Office servers and workstations. Serial cables are available with two types of connectors. The most common one is the DB-9 connector, but DB-25 connectors are also very common, especially with serial printers.
It is easy to mistake male and female connectors because of how they are built. The female DB-9 connector has 9 holes. The male DB-9 has 9 pins.
Again, it is easy to mistake male and female connectors because of how they are built. The female DB-25 connector has 25 holes. The male DB-25 has 25 pins.
Parallel or LPT printers connect through a factory-made parallel printer cable. On the computer-end of the connection, a DB-25 female connector is used. At the printer end, a female 36-Pin Centronics port is used.
Unshielded Twisted Pair (UTP) cables are typically used along with 8P8C (8 Pins 8 Conductors) modular connectors to connect Ethernet adapters to TCP/IP networks. In common networking “lingo”, the male connector is known as a Plug while the female connector is known as a Jack.
Note that 8P8C is the correct name for this type of connector. “RJ-45” actually comes from the expression “Registered Jack number 45”, which was used by a well-known telephone company using a similar connector.
There are two distinct types of 8P8C plugs. The type that should be used depends on the type of UTP cable being used. On the picture below, the plug on the left is designed to be used with Solid Core UTP cable, while the plug on the right is designed for Stranded Wire UTP cable. Notice the difference in the golden part of the plugs.
Unshielded Twisted Pair (UTP) cables are available in various categories. The most widely used are Category 5e for 10/100 Mbps connections and Category 6 for 1000 Mbps (Gigabit) connections. Category 6A was recently introduced to support connections up to 10,000 Mbps (10GBase-T Ethernet).
Among each cable category, there are two types of cables: Solid Core Wire and Stranded Wire.
Solid Core wire cables can cover greater distances than stranded wire, but they are generally more fragile. They are more prone to breaking if they are bent and twisted repeatedly. Solid core wire cables are also cheaper than stranded wire cables. Therefore, solid core cables are meant to be used in permanent runs, inside walls, ceilings, etc.
Stranded wire is more flexible than solid core wire. Therefore, it is more resistant to bending and twisting. Unfortunately, this type of cable is much less reliable than solid core wire as distance increases, and it is also more expensive. For all of these reasons, stranded wire cables should only be used for very short distances, or between wall jacks and network devices.
Cat 5e is the most common and cheapest network cable available. It supports network speeds up to 1000 Mbps (Gigabit Ethernet). According to the current ANSI TIA/EIA 568 standard, the diameter of the conductors within the cable should be no thicker than 22 American Wire Gauge (AWG) and no thinner than 24 AWG.
Cat 6 cable is designed specifically for Gigabit Ethernet (1000 Mbps), but it can also support 10GBaseT (10,000 Mbps) over short distances. Cat 6 cables are slightly bigger in diameter than their Cat 5e counterparts mainly due to a higher twist rate of conductor pairs within the cable, thicker sheathing and the introduction of a non-metallic spacer to separate conductor pairs within the cable. Cat 6 cables also use 23 AWG conductors, further contributing to overall cable diameter.
Cat 6A cable is designed specifically for 10GBaseT (10,000 Mbps). These cables are even bigger than Cat 6 cables. They also use 23 AWG conductors, but they have an even higher twist rate, thicker sheathing and a bigger non-metallic spacer between conductor pairs inside the cable.
Category 6e is not a standard, and is frequently misused because category 5 followed with 5e as an enhancement on category 5. Soon after the ratification of Cat 6, a number of manufacturers began offering cable labeled as "Category 6e". Their intent was to suggest their offering was an upgrade to the Category 6 standard—presumably naming it after Category 5e. However, no legitimate Category 6e standard exists, and Cat 6e is not a recognized standard by the Telecommunications Industry Association.
Each category of network cable (5e, 6, 6A) is also available in shielded versions that are referred to as either U/FTP or F/UTP depending on the type of shielding they have. Shielded cables offer superior performance and reliability in harsh environments with multiple sources of possible interference such as:
• Electrical wiring • Electric motors (such as HVAC systems, A/C or refrigeration equipment, etc.) • High-power electrical equipment (such as ovens, industrial equipment, etc.) • Wi-Fi antennas and devices
Unfortunately, shielded cables are generally much more expensive than their unshielded counterparts, and they require special shielded connectors which are also more expensive and harder to handle than standard connectors.
F/UTP stands for Foil shield over Unshielded Twisted Pairs. Basically, all 4 conductor pairs are wrapped in a single foil shielding. There is also a drain wire that needs to be grounded by using specially designed connectors.
U/FTP stands for overall Unshielded, Foil over Twisted Pairs. This type of cable has each conductor pairs individually wrapped in a foil shielding. This type also has a drain wire that needs to be grounded by using specially designed connectors.
In order to be effective, shielded cables need to be terminated with shielded 8P8C (RJ45) plugs and use a special conductor separator in order to avoid alien cross-talk between conductors within the connector. Also, very strict and manufacturer-specific precautions need to be taken when crimping shielded connectors to shielded cables. Please review manufacturer-supplied instructions.
