Knowing your angles

17 June, 2008

The configuration of patch cords and RJ45 plugs around cables has become far more critical in recent years, due to the fact that transmission speeds have increased from 10 Mbit/s in Cat 3 cabling to 10 Gbit/s in the latest Cat 6a cables. Until three years ago, IT technicians had no choice but to use flat patch panels and then purchase a separate management panel, comprising a flat piece of metal with rings mounted on the front, through which patch cords were arranged and aligned.

For horizontal solid-state cabling which is hidden behind walls and never moves, the installation engineer will have adhered to the standards on bend radii and all the wiring will be neatly laid out. However, people do tend to subject patch cords to 90° bends at the patch panel end in the rack or cabinet, to get them into the management rings, and then at the end of the frame as cabling is either plugged or unplugged to suit the changing configurations of the business.

The problem here is that a kink in copper cabling can cause a ‘return loss reflection’. This effectively means that, as the signal is transmitted down a cable, some of it bounces back which slows down data transfer and causes error rates to increase. We also have to remember that when the cord is bent some of the copper strands, by necessity, will be stretched and, while the insulation material will have certain ‘elastic’ properties, the copper has none.

It used to be the case that data transmission would only involve two of the four pairs in the cable (one pair would transmit and another pair would receive). However, nowadays, there is a higher demand for increased transfer speeds which often means that all four pairs transmit and receive simultaneously. Therefore, data is flashing backwards and forwards at massive speeds, meaning that a kink in one of the cables will disrupt the signal and slow it down.

In a typical situation, a patch panel will have a management panel underneath it which is the same size and has four metal rings coming off it at 90°, through which the patch cords are fed. What tends to happen is that the IT technician will bend the patch cord sharply to fit through these rings.

A possible solution to this problem is to use angled (or sometimes curved) panels. These include a 25° bend in the centre that is similar to a pitched roof, meaning that the patch cords follow a natural curve rather than being forced into sharp bends, as is the case with panels that comprise a flat piece of metal.

There are numerous benefits to this method. Firstly, there are fewer error rates and faster data transfer, due to the fact that the patch cords are set up correctly which, in turn, protects the network’s uptime, minimises disruption and optimises the system’s performance.

Secondly, they are space saving. In a typical installation, for every two patch panels there is one management panel. However, you do not need a management panel with angled or curved panels and, because of this, there can also be another benefit - that of cost saving (despite the fact that angled or curved patch panels tend to be more expensive than conventional flat versions), as the customer does not have to purchase a management panel.

Because it is easier to manage a system if it is properly patched and looked after, there is also a time cost saving. More importantly than looking like a tangled mess, a ‘spaghetti’ of cabling can cause all sorts of disorder as it makes it far more difficult to trace cables and identify their purpose. How can IT staff effectively manage a system if they can hardly see switches and patch panels because of intertwined cable?

Another benefit of angled/curved patch panels that shouldn’t be taken for granted is the dynamics of appearance. Senior managers can often spend hundreds of thousands of pounds on an IT system but, if when they walk into the IT room they are met with a tangled mess of wiring, they are bound to question what all the money has been spent on. On the other hand, a completely structured and managed system shows a level of professionalism among the IT staff and gives senior management confidence that their investment is being spent wisely.

Patch cords are the ‘tyres’ of a data network and the introduction of curved and angled panels is like the introduction of traction control. It will ensure the system lasts longer, runs more smoothly and runs at higher speeds.