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What Is Patch-by-Exception and Why Do We Need It?

Enterprise Infrastructure
Posted by James Donovan on 9 December 2016 Connect with James on LinkedIn Estimated reading time: 3 minutes

Patch-by-Exception

For engineers looking for an easy, inexpensive yet high performing cabling alternative, Patch-by-Exception offers a solid solution. Helping to save time and money while improving performance, manageability, security and aesthetics, we explore what Patch-by-Exception is, and the need behind its use.

Why We Need Patch-by-Exception

The most common method of installing communications cabling systems throughout the world is to utilize a standard RJ45 patch panel style solution.

While the RJ45 patch panel solution offers some advantages (for example patch-cord changes can be made by most staff, without the requirement of a qualified technician), the RJ45 patch panel solution also comes with certain disadvantages:

  • There are either no records kept, or it’s very hard to keep records up to date.
  • Unauthorized changes can be made without approval.
  • Testing of outlets requires disconnection of the service.
  • Patch cords required for every service.
  • Poor management can lead to a patch cable nightmare.
  • Takes up space in equipment racks.
  • Changes can be made to network equipment within the equipment rack.

Patch cord mismanagement and an inability to test/monitor circuits create a costly operational nightmare. The good news is that there is a better way, one that will not result in a tangled mess of patch cords – Patch-by-Exception.

What is Patch-by-Exception (PBE)?

Patch-by-Exception technology offers a superior patching solution while avoiding many of these issues associated with traditional RJ45 systems.

So how can we define PBE?

The following definitions come from satisfied users around the world:

  • “PBE is the ability to create a completely interconnected communications management system at the floor distributor without the entangled mess of patch cords or expensive patch cord management systems.”
  • “PBE is where hard wiring is used to connect circuits. This hard wiring can then be overridden by a patch cord making patching the exception rather than the rule.“
  • “PBE is a solution whereby you hard wire your network and make subsequent changes utilizing patch cords. To go back to the original configuration, simply remove the patch cords.“

Patch-by-Exception and Disconnection Modules

IDC (Insulation Displacement Connection) termination modules with their unique Patch-by-Exception design provide an easy and inexpensive cabling alternative. CommScope offers a Patch-by-Exception solution for Category 6 and 6A applications.

These Category 6 and Category 6A modules all contain disconnection contacts. It’s this distinctly unique feature that sets them above other IDC contact types. You can only achieve the benefits of a Patch-by-Exception solution by utilizing disconnect modules.

A disconnection module has two contacts for each wire, an ‘in’ and an ‘out’. These two contacts touch in the middle of the modules with a controlled amount of spring pressure.

The central spring contacts allow the single-wire circuit to be disconnected, hence the name ‘disconnection contact’, and provides the access for patch plugs, test plugs, monitoring plugs or isolation plugs.

Design of disconnection modules

The design of disconnection modules provides a clean front panel. The insulation displacement contacts for the wire and the disconnection spring contacts are recessed inside the module so accidental contact of the module with a metallic tool like a screwdriver will not cause any short circuits.

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During moves, adds and changes, the act of plugging a patch cord into the work area modules open the internal spring contacts, thereby disconnecting the existing circuit.

When the other end of the patch cord is plugged into the module on the network equipment field, it will disconnect that existing circuit and feed the signal via the patch cord to the new work area outlet.

The patch cord has therefore created a new patched configuration, bypassing the original hard-wired configuration. The patch has become an exception to the original, hence the name “Patch-by-Exception.”

To revert back to the original jumpered configuration, simply remove the patch plug from the network equipment modules, then the work area module.

This sequence ensures no signal voltages will appear on the plug ends. The patch cords can be hung in a cupboard ready for use the next time an exception is required to the original jumpering.