TELECOM ACCESS STANDARDS NEWSLETTER NO. 144 November 2003 CONTENTS 1. MAINTAINING VOICE PERFORMANCE STANDARDS 2. RADIO FREQUENCY EXPOSURE SAFETY OF CORDLESS TELEPHONES & HEADSETS 3. ADSL MODEM TESTING 4. ELECTRICAL SAFETY TESTING: PROPOSED CHANGES 5. RESIDENTIAL-TYPE WIRING - PTC 103 "DRAFT FOR PUBLIC COMMENT" 6. SOHO AND STAR WIRING HARDWARE - PTC 225 "DRAFT FOR PUBLIC COMMENT" RETURN TO MAIN INDEX 1. MAINTAINING VOICE PERFORMANCE STANDARDS Further to the articles on the quality of service of Voice over IP transmission performance in Newsletters 131, 134 and 135, the transmission design of the public network in general will shortly be addressed in a re-issue of TNA 151, Telecom's Telephone Network transmission Plan. The current version was published in 1997, so it does not take into account the IP-related matters raised in the above Newsletters, nor does it have any references to IP operation. The same basic message is still in place however - get the telephone instrument Loudness Ratings right and this gives more leeway for other impairments. Since our digital telephone Loudness Ratings are the same as those recommended by the ITU, this should be a simple compliance issue for CPE suppliers. Similarly, since most analogue telephones are now chip based, with Loudness Ratings set by the appropriate choices of component values, the cost of achieving the optimum values of Loudness Rating is unlikely to be higher than for achieving the wrong values. Test labs and suppliers are reminded that we have also tightened the tolerances on all Loudness Ratings to ± 3 dB, as announced in Newsletter No. 130. The current requirements are:- SLR RLR Analogue: + 2.0 dB minimum (Loudest) - 9.5 dB minimum (Loudest) - 14.0 dB with receive volume control + 5.0 dB objective - 6.5 dB objective + 8.0 dB maximum (Quietest) - 3.5 dB maximum (Quietest) Digital: + 8.0 dB objective + 2.0 dB objective We are also working on the revision of PTC 200, but this was delayed while we reviewed potential network changes. The revised PTC 200 will also align with the Loudness Ratings and tolerances stated in Newsletter No. 130. 2. RADIO FREQUENCY EXPOSURE SAFETY OF CORDLESS TELEPHONES AND HEADSETS A recent enquiry raised the question of the long-term safety of cordless headsets which, unlike cordless phones, are commonly worn for most of every working day by operators at call centres and other full-time telephone operator locations. The following information applies to all cordless phones or headsets, which have integral antennas and are used close to the head of the user. NZS 2772, a voluntary standard, states that for general public user equipment, the Specific Absorption Rating (SAR) must be measured or calculated if the power exceeds an average of 20 milliwatts. To fully comply with this New Zealand Standard, many cordless devices should have an SAR measurement or be checked by calculation. There are two recognised measurement standards: FCC OET Bulletin 65 and IEEE 1528-200X of 2002 (which are used for Telecom's cellphones); and the European Standard EN 50361: 2001. Both measure the energy transmitted into body tissue, the EU test using a 10 gram sample and the FCC test using a 1 gram sample. The NZ Standard permits an SAR of up to 2W/kg averaged over any 10 gram. This is the same as the Australian requirement. Most cordless headsets are designed for very short range use and thus inherently have low power outputs in the 1 - 100 mW range. Similarly, most cordless phones are short range devices. Products sourced from Europe are required to comply with SAR limits under Article 3.1a of the R&TTE Directive, but those from the Far East may not meet such requirements, unless they have already been supplied to the Australian market. For Australia, the ACA have published a summary of their requirements, which can be viewed on: http://www.aca.gov.au/consumer_info/issues_alerts/emrbook_regulatory.htm This URL provides links to the actual testing specifications and technical regulations. All in all, SAR compliance is not expected to be a problem for headsets or cordless telephones - unless they are long-range versions. Telecom requires that cellphones used on its network are checked for strict SAR compliance at maximum power output. In practice, SARs are normally lower than the maximum, as the network significantly reduces the cellphone power output for the vast majority of calls. While it is not yet mandatory in New Zealand, it is recommended that local importers seek SAR compliance certificates from their manufacturers for all cordless devices. By doing this, products should be fully compliant with any NZ regulations that might be introduced in future and customers can have greater confidence in the products concerned. 3. ADSL MODEM TESTING Telecom is now introducing its "mini-DSLAM" to provide ADSL services for small groups of customers for which there was either no direct copper access from the local exchange or where service by the previous DSLAM's was not economic. Our original ADSL services were provided by Nokia DSLAM's, but current and recent purchases of DSLAM's have been from Alcatel. The "mini-DSLAM" referred to above is from a US company, Conklin Intracom. In total, there are now six different variants of DSLAM line cards in service, but all are compliant with ITU Recommendation G.992.1 and also support the US standard, T1.413. Nevertheless, with such complex specifications, there could be subtle implementation differences by these DSLAM manufacturers. Similarly, each modem manufacturer may be introducing features or minor variations, such that every modem line interface is not always identical from a compatibility viewpoint. Service experience to date has revealed that there is only a small risk that any particular modem may not work 100% with a particular DSLAM. There are now nearly 120 different ADSL modems holding Telepermit, each potentially connecting to any one of the six different DSLAM's. Adding to this is the wide variation in line attenuation across the access network. Despite all these possible permutations, we have had very few combinations of specific modem types and DSLAM types not operating together effectively. Nevertheless, there is always the possibility that problems may arise, even though the risk seems low. Our two PTC 270 test laboratories carry out some of the verification testing under "live network conditions", but only on their own lines and using a single DSLAM. This keeps testing costs down, but does not 100% confirm that a modem will work with all DSLAM types. Telecom is providing its JetStream Help Desk with access to all six types of DSLAM card and with varying length test lines. All ADSL modems supplied by Telecom are to be put through a test programme to confirm that there are no combinations that do not synchronise properly. Should the results of these tests indicate that there are some problems we are currently unaware of, we may have to increase the scope of testing defined in PTC 270. More will be published on this issue when we have had the opportunity to review the results. 4. ELECTRICAL SAFETY TESTING: PROPOSED CHANGES For electrical safety compliance purposes, Telecom has generally aligned with the Australian practice of using the 1993 version of AS/NZS 3260 as the minimum level of compliance. Most CPE products sold here are also sold in Australia and this was a joint AS/NZS standard in any case. However, the IEC has since advanced the issue of its original standard, IEC 950, on which AS/NZS 3260 was based. This became IEC 60950: 1999, which was subsequently adopted as AS/NZS 60950: 2000, with a number of mainly Australia-specific deviations. It has since had Amendment No. 1 added, and then further advanced to IEC 60950.1: 2003 The ACA's Technical Specification TS001, which required compliance with the 1993 version of AS/NZS 3260 and its four amendments, is being withdrawn. The ACA will instead require compliance with AS/NZS 60950:2000 (excluding Amendment No. 1, which was published in 2003). This change has just been Gazetted in Australia. This allows an overlap period until the end of June 2004, during which compliance with either TS001 or AS/NZS 60950:2000 is acceptable. This change in Australia provides an opportunity for Telecom to up-date its electrical safety requirements and formally withdraw PTC 101, which is now rarely used. The timing for withdrawing acceptance of test reports to the 1993 edition of AS/NZS 3260 is yet to be decided, but this will probably be about mid-2004. We are already getting some applications with test reports to AS/NZS 60950:2000 and, of course, test reports to the 2003 edition are equally acceptable. CPE suppliers should note that Telecom does NOT require compliance with the Australian deviations, as our conditions here are not so onerous. As a result, we also accept overseas-produced compliant test reports to IEC 60950: 1999 and its direct national equivalents. Stand-alone transformer-based power supplies continue to be subject to AS/NZS 3108. Stand-alone switched mode power supplies are more appropriately covered by AS/NZS 61558. 5. RESIDENTIAL-TYPE WIRING - PTC 103 "DRAFT FOR PUBLIC COMMENT" PTC 103, our Code of Practice for Residential-type Premises Wiring has been revised to cover a number of issues which have come up since it was published in 1997. The requirements of the 1997 edition are essentially unchanged, but the additions include:- * Recommending star wiring with Cat 5 cable for all new work; * Up-dating references to SOHO in relation to star wiring; * References to ADSL and its associated wiring; * Clearly excluding RJ 45 jackpoints and cabling hardware (including dual RJ/BT jackpoints) from our wiring maintenance service; * Dropping the use of 3-w jacks for new residential wiring, now these no longer hold Telepermits; * References to the process for transferring customer's wiring to other networks; * Explanation of Telecom's inability to cable across private land without the owner's permission; * Coverage of gate and door entry systems, explaining that these need Telepermit and authorisation by all customers concerned; * References to Network Terminating Equipment, now termed Customer premises Located Network Equipment (CLNE) and its cabling; * Screened twisted pair (STP) cabling excluded from the scope of the document, but shown as being subject to special conditions as regards supplier/installer support; The mandatory requirements are now shown in our usual way, by shading them so they stand out. These align with the 1997 version wherever it used the word "shall". The "Draft for Public Comment" is now published on our website as http//:www.telepermit.co.nz/PTC103_2003draft.doc The 1997 version remains "in force" until the new version is finalised early in 2004. In the meantime, comments and suggestions are invited. 6. SOHO AND STAR WIRING HARDWARE - PTC 225 "DRAFT FOR PUBLIC COMMENT" PTC 225, which covers "Telecom requirements for Star Wiring Boxes and Small Office/Home Office (SOHO) Cabling Installations", is also now published as a "Draft for Public Comment". This also follows the earlier version fairly closer in most respects, but now includes requirements for the simpler star wiring boxes as well as SOHO installations. This recognises that the BT jackpoint is still the basic Telecom standard and most widely used in the home or small office environment. It allows for jumpered cross-connections, as these reduce costs and will meet the requirements of most home customers, who do not rearrange their wiring very often. SOHO goes beyond this by providing RJ 45 sockets and cross-patching facilities. SOHO is currently covered by AS/NZS 3086: 1996, but a new edition is expected in 2004. This is expected to align far more closely with AS/NZS 3080 and be in most respects a sub-set of this commercial cabling standard. The URL for the "Public Comment" draft of specification PTC 225 is http://www.telepermit.co.nz/PTC225_2003draft.pdf Comments and suggestions are invited, especially from those suppliers offering SOHO and Star box hardware. DOUG BURRUS Manager Access Standards