TL 9000

Picture of Telecommunications at DuskFor some time, it has been recognized that communications and IT equipment have not always been at the forefront of reliability when compared to other industry sectors. Many would argue that the reason for this is the consistent demand placed on manufacturers to supply products that are at the cutting edge of new technology.

However, in the telecommunications industry, it is not only component and software failure but also poor delivery by suppliers of service that can result in a serious loss of revenue for service providers. It has been recognized that there is a clear need for an answer to these growing concerns.

Representatives from the industry, originally mainly USA based, but now encompassing representation from Europe and Asia, established the Quality Excellence for Suppliers of Telecommunications Leadership Forum (QuEST). The QuEST Forum has developed a common set of quality system requirements and measurement metrics for suppliers of telecommunications systems hardware, software and services. These requirements, contained in TL 9000 Books 1 and 2 respectively, are built upon industry standards already in use, including the well-established ISO 9001 standard.

The Purpose of TL 9000

The purpose of TL 9000 is to define the telecommunications quality system requirements for design, development, production and service. In addition, it specifies the cost and performance metrics for suppliers to measure progress and evaluate the results of quality implementation and improvement programs.

Whilst many of the principles of TL 9000 were established by the network operators' specific requirements, e.g. Bell Corporation standards, these have been "globalized" by industry representatives through QuEST Forum working groups, made up from a broad spectrum of interested parties. Participation in the working parties is dependent upon QuEST membership (visit for more details). NQA is an active participant in the Supplier Chain Group and the UK industry sector representative body, the Telecommunications Quality Forum (TQF) hosted by the TIA (Telecommunications Industry Association). More information on the TIA can be found at TL 9000 initiatives have been widely accepted by telecommunication companies in the USA and Asia, with TL 9000 becoming a common purchasing specification further afield, including the UK, as the drive for increased reliability and cost effectiveness in the industry continues to be a major factor.

To Whom it Applies

TL 9000 was originally aimed at first tier suppliers to the telephone network operators, however, new product category tables and a clarification of the Book 1 and Book 2 requirements for indirect suppliers has made it more acceptable down the supplier chain. More recently, the inclusion in the scheme documentation of customer premises equipment indicates that the scope of TL 9000 could be broadened to include suppliers not previously thought to be included, if called for in purchasing documentation.

NQA became the first UK based Certification Body accredited by the RAB and recognized by QuEST in February 2001. TL 9000 accreditation supplements a full portfolio of services to the telecommunications sector, which includes Notification for Annex V of the Radio and Telecommunications Terminal Equipment Directive (Full Quality Assurance Approval).

What is the TL 9000 Structure?

The TL 9000 model is structured in layers comprising:

  • ISO 9001
  • Common TL 9000 requirements
  • Hardware, software and services specific quality systems requirements
  • Common TL 9000 measurements
  • Hardware, software and services specific measurements

The Quality System Requirements

The quality system requirements are described in Book 1 of TL 9000. Release 2.5, based upon ISO 9001:1994, includes one additional clause dealing with improvements and customer communication (4.21) and 84 supplementary requirements. Release 3 integrates this clause in a structure that is based upon ISO 9001:2000. Both releases reflect the structure above.

The Measurement Metrics

Measurement performance and product statistics are specified in TL 9000 Book 2. The measurement data produced is intended to identify opportunities for improvement in the customer/supplier chain and to benchmark performance against suppliers of similar product and services. Metrics reporting has been an area of contention in the past, with QuEST seeking to provide a balance of its perceived needs whilst recognizing that metrics of a similar nature are already produced in Europe for other purposes. Working groups in the USA and Europe meet to resolve conflict and duplication of effort with common ground being recognized.


In addition to meeting ISO 9001 and the supplementary requirements, it is important that the applicant has appropriately trained staff. Currently, the QuEST Forum sanctions two courses - a three-day course dealing with the quality system requirements and a four-day course that also includes the metrics aspects. The "Excel Partnership" is currently the sole UK organization accredited by QuEST to provide this training.

The Future

TL 9000 has attracted a great deal of attention in the USA. Initially the reception in Europe was less enthusiastic, with a significant number of the principal network operators questioning the benefits claimed by QuEST. As more Europeans join the debate, their views are heeded and a less polarized position is apparent.

For additional information, the TL 9000 website is: or you can contact NQA.

Once registered to TL 9000, NQA-registered clients can have their TL 9000 surveillance visits integrated with their ISO 9000 surveillance visits. E-mail for more information.

We have written this TL 9000 Guidance Document to help you understand the registration process.

Download a PDF of the TL9000 Registration Services.

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Page updated on 4/10/2014