STFbreadcrumb separatorSTFsbreadcrumb separatorSTF Homepagesbreadcrumb separatorSTF358

Specialist Task Force 358:
Update of TBR38 for Speech terminals with PSTN access, when implementing tests with HATS –
Head And Torso Simulator

Who we are:

Team Leader and expert:    Jean-Francis Dolidet  

Why we do it:

TC STQ has developed a program based on wideband speech. In this context, new standards for speech terminals have been created  TC STQ has also provided or proposed support to other bodies (e.g. TC DECT) in order to have compatible standards guaranteeing a high level of Quality for wideband speech transmission.

When developing wideband speech terminal standards, and considering the designs of new generation handsets, it was needed to implement test methods based on the use of HATS (Head And Torso Simulator) to qualify the electro-acoustical performance of terminals. As the most of the terminals implementing wideband speech (150 Hz to 7 kHz) also supports narrow-band speech (300 Hz – 3400 Hz), it was logical to use the same test equipments for the different bandwidths.

In some cases, new terminals may be associated with PSTN access, through gateways, wireless bases etc… which need to fulfil PSTN standards such as TBR38.  However, as TBR 38 is an "historic" standard, the test methods have not evolved as the design of the new speech terminals. To solve this issue, a new set of test methods have to be implemented in an updated version of TBR38, these methods being based on the use of HATS. It shall be noted that the update will not affect the existing test methods which will remain as they are, but will add new test methods applicable to new speech terminals with PSTN Access.

For more details, see our Terms of Reference

How we do it:

As TBR are no more produced by ETSI. The content of the ES that will be produced as an update of the TBR38 will need to:

  • extract from TBR 38 the relevant requirements and test methods that will remain in the EN, in order to maintain the contents similar to the existing ones for PSTN designed for TBR38
  • identify the new test methods and requirements to be included for new speech terminals to be tested with a HATQS
  • adapt the test methods using HATS to ensure compatibility in the requirements between TBR 38 and the updated standards.


Four tasks have been identified. Except task 1 that will be done first, the 3 other tasks will progress in parallel:

  • Task 1: to create an EN based on the existing clauses of TBR38
  • Task 2: to adapt the new methodologies both to PSTN access and  parameters (and associated test methods) defined in TBR 38 This task will begin by a collection, a review and an analysis of the existing materials (in TC STQ and other SDOs).The result will be the new draft EN
  • Task 3: to test 2 speech terminals in order to ensure that the updated test methods and associated requirements are finely tuned.
  • Task 4: to organise conf calls and e-mail discussions and to participate to STQ meeting in order to finalize the document


Task 1 will be presented at STQ#29 meeting, and a discussion about evolution of this draft will be conducted.


Task 2 and 4 will be conducted using existing standards and points of discussion will be solved by e-mail of conf-call. A stable ES draft will result from those tasks.


Task 3 : 2 PSTN terminals will be tested according the ES draft and results will be examined in order to see wether new requirements are realistic.

Time plan for the work:

The STF will produce the following deliverable, for TB approval: DEN/STQ-00129 - attachment requirements and test methods for terminal equipment incorporating a handset function connected to the analogue interface of the PSTN, according to the following time scale:

  • Start of work:                                end September 2008
  • Stable draft for TB approval:         14 November 2008
  • TB approval:                                 STQ#30 meeting (1-5 December 2008)

How to contact us:

STF Leader and expert : Jean-Francis Dolidet TES Electronic Solutions

Tel : (33)2 98 10 30 15

Fax: (33)2 98 10 30 01

Postal Adress : 50 rue du Pdt Sadate  29337  Quimper Cedex. France


This information is based upon STF working assumptions.
The views expressed do not necessarily represent the position of ETSI in this context.

Last updated: 2013-04-13 17:31:06