Computer Cable Assemblies Overview

Computer cable assemblies include a length of cable with the connectors prewired to the cable. They come in designs intended for general office use as well as in designs that are intended to be used in harsh industrial conditions. They are manufactured by a huge number of different companies, with names such as RS, Phytec and TE Connectivity being common brands for these products.

There are many different types of connectors in use, some of which have been in use for decades. The most popular types, including USB, have been revised over the years, allowing for faster data transfer rates. When outfitting older equipment with cables, it’s sometimes important to check whether the new equipment is backwards compatible. Most USB connectors, for example, are, but this is not always the case.

 

Adapting to Newer Connectors

In some cases, cable assemblies provide a way to keep on using older equipment. VGA connections, for instance, were once standard for computer/monitor connections. Today, DVI connections are much more common. By having cable assemblies with DVI and VGA connectors, an old monitor or old video card doesn’t need to be disposed of.

Some types of connectors become outdated—or “legacy”—devices, but remain in widespread use, even though there are more convenient options available. The PS/2 connection on most new computers, for instance, is a legacy port according to some manufacturers, but it is still widely used. USB ports are used for the same purposes as PS/2 ports, connecting keyboards and mice to computers, but having the legacy ports does have its advantages. It allows for USB ports to be freed for other uses.

A similar situation is true of parallel ports. These ports have been widely displaced in consumer electronics by USB ports, but are still used in industry, particularly in development, because they are an easy means of attaching circuit boards together. Older equipment that is still in use may also make use of parallel connections, requiring that the connectors remain on the market for such uses. Many new computers, however, are not shipped with parallel ports, vastly reducing their usage on office computers.

Serial cables are also in use, though they are also considered legacy hardware. Like parallel connections, however, serial connections are suitable for development and are very inexpensive compared to some other types of connectors, which makes them useful still.

 

Considerations for Cables

For industrial usage, some of the cable assemblies required will be identical in terms of connectors as consumer cable assemblies. However, those assemblies are not typically designed to hold up to the environmental threats and heavy usage these cables will receive in an industrial setting. Some of these cables will not be able to dissipate heat quickly enough under heavy usage and may actually burn out because of this.

In addition to selecting cable that is appropriate for the intended usage, it’s important to handle cable correctly when it’s in use.

 

Protecting Computer Cable Assemblies

No matter how durable a computer cable assembly is built, there will be limits to how much mechanical and environmental stress it can tolerate. It’s important to minimize both.

For very hazardous environments, there are computer cables connectors that are threaded or otherwise secured that reduce the risk of the cable being torn out of its socket or being damaged by materials in the environment.

The cables themselves are available in many different colours. This aids in organizing the cables, but also can provide a warning in instances where cable runs present a trip hazard.

Computer cable assemblies come in many different lengths. It’s generally desirable to have extra length, but some types of cables have diminished performance when they get beyond a given length and this has to be taken into account. Extra lengths of cables should be gathered up and secured with cable ties. This prevents the cables from being damaged and prevents people from tripping over them, harming themselves or the cables.

 

Cables for Internal Use

Some computer cable assemblies are designed to be used inside a computer case or inside the housing of other equipment. This type of cable has to be selected so that minimal length has to be secured. In some applications, the cable may be routed around the case in specific channels to increase airflow and cooling. Cables have to be long enough to accommodate this.

Internal hardware is subject to the same changes in popular connectors as is external hardware. SCSI connectors were once very common, but now most hard drives use SATA connections, as they offer better performance. Older hardware sometimes requires cables that are no longer popular on the market, but industrial electronics suppliers have them available. They can also be combined with multiple types of connectors.

This makes it possible to link together power supplies and newer hardware that might use a different type of connector, for instance. Splitting cable assemblies allow one power source to be used for multiple devices, but it’s important to know how much more electrical energy is being provided by the power supply when using these, and whether it might actually cause damage.

The various internal connections available are differentiated by pin count, shape and other specs.

 

Installing Computer Cable Assemblies

Many computer cable assemblies are designed to be very easy to plug and unplug, such as is USB. Other’s however, particularly internal cables, require a bit more consideration when they are connected or disconnected from ports.

 

Internal Computer Cable Assemblies

Internal computer cable assemblies are generally very easy to install. The various types of connectors on motherboards are designed so that the wrong connector cannot be plugged into a port.

When inserting these connectors, they are typically held directly in-line with the port and snapped into place. There should be very little or no resistance when inserting the plug. Plastic snaps hold most of these in place, which much be released before the cable can be removed.

An internal computer cable that resists being unplugged from or plugged into a port should never be forced. This always means that there is a misalignment, some sort of compatibility issue or damage to the port that prevents the cable assembly from sliding into place. Forcing the cables can damage the ports and the PCB to which it is connected, as well.

 

External Computer Cable Assemblies

USB, Firewire and even parallel connections are designed to be easy to connect and disconnect. They may have modifications for particular hazards, but most USB cables and Firewire cables simply plug in and are pulled out by light force on the end of the cable.

Parallel and other type of computer cable assemblies sometimes come with thumbscrew attachments. These consist of two threaded screws on each side of the adapter that allow it to be firmly screwed into two matching holes on the port. These are ideal for situations where mechanical force is a real and constant threat.

Other types of connectors have a mechanism that snaps them into place, which also secures them well, but not as tightly as screws. Which connection type is chosen should depend upon the operating conditions under which the computer cable assembly will be used.

Different colours are convenient, and may actually provide good safety advantages in some applications. In hazardous environments, one should check the datasheet for any computer cable assembly being considered to be sure that the materials it’s made out of can hold up to the conditions.

 

Common Types of Computer Cable Assemblies

The types of assemblies on the market change constantly as new connectors and technologies are introduced. Constant demand for faster data transfer speeds also drives innovation in connections and cables.

Some computer cable assemblies are so common that they are known by names that do not describe the actual connector. A 5.25 inch, four-pin power connector, for instance, is known as a Molex. The name of the connector has nothing to do with the connector itself, but is taken from a company that manufacturers these connectors. Firewire is clearly more of a marketing term than an engineering term, with the actual designation of these cables being IEEE-1394, see below.

 

Firewire

Firewire is officially known as IEEE-1394. It is associated with Apple Computers, which developed the technology, but has become fairly common since it came onto the market in the 1990s. It has a transfer ceiling of 400 Mbps and is used extensively with media applications. A new standard, Firewire 800, doubles the transfer speed.

 

Digital Video and Monitor Cables

These cables are specifically designed for use with media and can transfer large amounts of data, allowing for very high-quality video. The interfaces include HDMI, DVI and others.

 

Power Cables

Power connectors provide connections between the power supply and the mother board, hardware and peripherals. They come in AC and DC versions and in configurations designed for use with many different types of connectors.

 

SCSI

SCSI stands for Small Computer Systems Interface. The cables using these connections come in designs that are intended to be used inside the computer case and in designs that can be used to connect external devices. There are three types of SCSI cables, differentiated by how each of them sends signals.

 

USB

USB is a newer technology and one of the easiest to use. It is also very common and there are variations on the design, such as mini and micro USB connectors. The current version of USB technology is USB 3.0.

 

 

Computer Cable Assembly Kits

These include cables supplied with standardized connectors and the hardware that is used with them. These kits can be used to replace damaged parts or for new builds. SMT and other types of connectors are available. This category also includes the tools used to extract cables and other related items. Manufacturers include RS and TE Connectivity.

 

Computer Power Cable Assemblies

These include power cables as well as power adapters, which allow one type of power connection to be interfaced with another. An ATX to AT connector is an example of the latter available from RS. They also include 1 to 4 connectors and many other options for motherboard connections and more.

 

Digital Video and Monitor Cable Assemblies

This range of products includes connector types such as DVI, HDMI, SVGA and other options. Current ratings run from 0.5A to 3A and there are many different lengths available, along with options for sheath colours.

 

Firewire Cable Assemblies

These assemblies include options for pin and pole counts, multiple connectors on the same cable assembly and more. They come in lengths as long as 5 meters and a variety of manufacturers, including Phytec and RS, produce these assemblies.

 

KVM Mixed Cable Assemblies

KVM (Keyboard, Video, Mouse) cables allow techs to use the namesake devices to control more than one computer. They come in many different configurations, allowing for PS/2, VGA, RS232 and other connections to be utilized.

 

Parallel Cable Assemblies

Parallel cable assemblies include options to have different connectors on the end of each cable. The come in very long lengths, up to 10 meters, and with options for sheath colour.

 

PS/2 Cable Assemblies

PS/2 connectors are very common hardware. This category includes standard PS/2 cables with options for male and female configurations, as well as associated hardware such as blanking plates.

 

SCSI Cable Assemblies

SCSI I, II and III are represented in this category, from manufacturers including Harting and RS. The cables include options for fasteners, including thumbscrews and clip fasteners. The cables can be assembled in different male/female options.

 

Serial Cable Assemblies

Serial Cables come with a variety of connector types, including SATA, IDC, eSATA, CDS 25F and others. These cables are manufactured by many large electronics companies. Options for populated pathways are also available.

 

USB Cable Assemblies

Micro USB, Mini USB, USB and other connectors are found under this category, and can be combined with different types of connectors on the same cable assembly. This is one of the most common and popular types of connectors in use in industry. There are also options for using USB connections in harsh conditions.