Network Equipment Building System

What is NEBS and why is it important? Long a requirement for equipment used in the Central Office in the North American Public Switched Network, the rigorous Network Equipment Building System (NEBS) criteria have become a universal measure of network product excellence. The NEBS compliance of GDC's products is a key advantage for access providers including Local Exchange Carriers (LECs), Competitive Access Providers (CAPs), Competitive Local Exchange Carriers (CLECs), Internet Service Providers (ISPs), and Access Service Providers (ASPs). Products that are NEBS certified are also expected to be top performers in enterprise net- work environments as well.

 Q: How and why NEBS was developed?

All electronic equipment has the potential to interfere with other electronic equipment. Interference can be caused by electromagnetic radiation, the grounding system, the electrical power connection, excessive heat or blocking the natural air flow, and connecting wires or cables. The FCC (Federal Communications Commission) regulates a portion of this problem through Part 15 of their rules and regulations, which specifies a maximum allowable amount of electromagnetic radiation from an electronic device in a commercial or residential environment at specific frequencies.

 Another standard that addresses the issue of collocated electronic equipment is NEBS. Telephone companies typically place a large amount of network equipment, often from different manufacturers, into relatively tight association, especially in their central office buildings. To address this, they gathered the best thinking from the FCC and various national and international trade and standards groups to create a set of specifications for network facilities located equipment. Originally developed by Bell Telephone Laboratories in the 1970s and expanded by Bellcore, these requirements are known as Network Equipment Building System (NEBS) Requirements.

 The most referenced documents in the United States telecommunications industry on the subject, the "NEBS Criteria" as they are usually called, are designed to help assure that the equipment purchase is easy to install, operates reliably, and efficiently occupies building space. The expectation is that physical configurations and compatibility of equipment with a set of environmental conditions will help to reduce product installation and maintenance costs.

 Bellcore introduced the NEBS requirements in 1985 as a public document, with manufacturers of central office equipment as the target audience. This introduction extended the principles from the pre-divestiture Bell Labs focus of telephone companies to the growing industry of equipment manufacturers supplying a broad range of telecommunications equipment.  


Regional operating companies and inter- exchange carriers require NEBS compliance. NEBS is a baseline for vendor selection and deployment by a new generation of service providers, such as competitive local exchange carriers, Internet service providers, independent telephone companies and others.

 Q: Briefly, what is specified in the NEBS requirement?

 Even more stringent than the FCC Part 15 requirements, NEBS covers a large range of requirements including criteria for personnel safety, protection of property, and operational continuity. The Bellcore documents cover both physical requirements including: Space Planning, Temperature, Humidity, Fire, Earthquake, Vibration, Transportation, Acoustical, Air Quality and Illumination; and electrical criteria including: Electrostatic Discharge (ESD), Electromagnetic Interference (EMI), Lightning and AC Power Fault, Steady State Power Induction, Corrosion,, DC Potential Difference, Electrical Safety and Bonding and Grounding.

 Q: What are the objectives of these criteria? NEBS criteria are designed to accomplish the following:

   Ensure equipment compatibility with the telephone industry's electrical environment

   Simplify equipment planning and installation

  Protect telecommunications equipment from service outages caused by incompatible equipment  

  Prevent interference to licensed radio transmitters and other close proximity telecommunications equipment

   Minimize the risk of fires to telecommunications equipment

   Ensure equipment operation under the range of temperature, humidity, vibration, and airborne contamination present in telecommunications locations

   Ensure equipment and service survivability in the event of earthquake  

  Protect personnel from injury

Q: Does NEBS have any importance beyond the telephone company world?

 NEBS is a major test of quality that is extremely valuable for any organization supplying or purchasing network equipment. A product that is NEBS certified has passed a suite of tests ensuring that the product will: operate reliably and be serviceable; not negatively affect other service providing equipment; operate properly in adverse environmental conditions; and not cause harm to the environment or personnel. Non-NEBS certified equipment may cause operating problems with other equipment, either instantaneously or over a long period of time. This equipment may also not perform properly or have a high failure rate and may result in very difficult to isolate network problems or failures.

301-924-7400 EXT 25

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