TELECOM ACCESS STANDARDS NEWSLETTER NO. 132 JANUARY/FEBRUARY 2002 CONTENTS 1. CABLE AND HARDWARE FOR RESIDENTIAL-TYPE PREMISES WIRING 2. TELEPERMITTING PRINCIPLES 3. TELEPERMIT RESERVATIONS 4. V.92 MODEM REQUIREMENTS 5. CALL WAITING DETECTION 6. PTC 200 AND TNA 102 NOW ON-LINE 7. ACCESS STANDARDS STAFFING CHANGES RETURN TO MAIN INDEX CABLE AND HARDWARE FOR RESIDENTIAL-TYPE PREMISES WIRING It has been reported that a lot of residential-type cabling is still being carried out in the old 3-pair 0.4 mm conductor cable, Telepermitted in the PTC 204-series. The exact amount is unknown, but installers should be aware that this older-style cable offers a much lower level of performance than the more recent 0.5 mm conductor cables, which have been Telepermitted in the PTC 222-series. ALL new installations should be carried out to either the Telecom standard 2-wire system or to the more complex SOHO practice (AS/NZS 3086), as described or referenced in Telecom Code of Practice PTC 103 (available free of charge on our website). SOHO is probably justified only for or those customers with a known need for a LAN, as it is a lot more expensive. This uses 4-pair cable of at least Cat 3 performance and, preferably, Cat 5 or better. Clause 3.2.1 of PTC 103 and the associated diagram allow for "star" wiring, which provides for better flexibility than "daisy chain" or "looping" used in the more traditional telephone wiring. It would be of advantage if hardware suppliers were to offer a suitable range of "star point" connection boxes and hardware for Telepermit. So far, none have taken up this option, but it would be particularly handy for customers who wish to connect alarm systems, line break-in devices, routers, etc, at a central point from which all jackpoint cabling would radiate. The increasing use of ADSL and other broadband services over telephone wiring means that a future need for cable offering a better performance than the old "legacy telephone wire" is almost certain. There is also the issue of radio interference from earlier cables carrying RF band signals and RF interference being induced into to these cables in areas close to radio transmitter sites. These potential problems can also be reduced by using the later types of cable and "2-wiring". Installers are to avoid the use of the older style cables in ALL cases, even if this does involve the up-grading of earlier 3-wiring wiring to the later 2-wire standard. In NO circumstances should PTC204-series cables be used for new 2-wire installations. In view of this, the Telepermits for PTC 204-series cables are now being expired, as warned in Newsletter No. 111, back in March 1999. The suppliers concerned will be advised accordingly. 2. TELEPERMITTING PRINCIPLES We continue to get numerous enquiries on how the Telepermit system copes with multi-module products like PABX systems, product variants and variations, so the following may be of general interest to readers:- General principles a) Every unique piece of hardware/firmware affecting network compatibility and compliance with PTC specifications must be tested to the appropriate specification. b) Every unique product (meaning a specific product "brand/name" for marketing purposes) must have its own Telepermit. c) Every importer of a product (even the same product) will generally have a separate Telepermit. NOTE: The above principles apply to products connected directly or indirectly to the Telecom network. In the latter case, a product may not even directly connect "behind" another Telepermitted product but, if it has characteristics that impact on network compliance, it will be subject to Telepermit requirements. An example of this situation is an IP phone, which may be connected via a router and a Gateway to the Telecom ISDN. The IP phone determines the transmission performance and the Gateway determines ISDN compatibility, so both will require Telepermit. However, where the router is "transparent", it does not need to be Telepermitted. Every product granted a Telepermit is required to be labelled. This not only shows prospective purchasers that the product may be lawfully connected to Telecom's network, but also indicates to Telecom which importer or supplier is responsible for its compliance. This is particularly important now that parallel imports of internationally-branded goods is permitted here. Using the PTC number any party may access the Telepermit register on our website to determine the Telepermit Holder as a potential source of product support. All in all, the basic aim is to ensure that CPE products are compatible with the Telecom network and remain so, independent of subsequent design and/or component changes. Multi-module systems A PABX is s good example of a multi-module system. Typically, these consist of a central processor and power supply, various line interfaces and proprietary terminals, plus a host of miscellaneous internal parts, such as registers, DTMF receivers and senders, peripheral interface cards, etc. Our general approach is to Telepermit each distinct system, covering any modules which are an inherent part of the system within the system Telepermit. ISDN line interfaces and proprietary terminals are all "optional add-ons", sold separately, tested to different specifications, and thus Telepermitted separately. A power supply built into the system cabinet is part of the system, whereas an external power supply - especially a general purpose one that can be used for other applications - is given a separate Telepermit. Needless to say, some latitude is needed on these general principles to cover other situations. For example, instead of having different sized systems in different sized cabinets with different model numbers, we have systems which simply add cabinets and change central processors to upgrade to a larger installation. In such cases, the basic system, as initially installed, would generally be granted a Telepermit. If the system designation does not change as it is "grown", it may be necessary to grant separate Telepermits to the replacement processors. Product variants Many products may be based on a common core design or may incorporate a standard line interface module of some sort. It is acceptable for the same test report to cover two or more variants. In these cases, each variant will be granted a separate Telepermit, but our application processing charge will be reduced if the two or more items can be dealt with at the same time. Variations New Zealand is a very small market in world terms and the number of different competing product designs on the local market means that NZ importers are almost always going to be buying in small quantities. As such, they will usually be provided with part of a larger batch being manufactured at the time their orders are being fulfilled. Minor component and design changes are thus almost inevitably going to creep in between individual orders. This might be termed a "fact of life". Since Access Standards has no view of follow-up orders, the only practicable way of maintaining compatibility is to require the Telepermit holder to confirm this in accordance with the undertakings made at the time of the initial Telepermit application. This is the reason for having a signed undertaking to comply with PTC 100 on the front page of the Telepermit application form. Because one importer can hardly be responsible for other batches of the same product which have been "parallel imported" by another party, each importer is required to hold a separate Telepermit and to ensure that those products under his/her control remain compliant with the relevant specifications, notwithstanding any design or component changes. With respect to product changes:- A product may have its internal circuitry changed at some point within the product life cycle, but still maintain the same functionality and product name. This applies also to component changes. If the changes could affect Telepermit compliance, then the product would need to be re-tested. A new Telepermit may not need to be applied for, unless the test results were so different from the originals that substantially different special requirements or User Manual warnings will be necessary. EMC and electrical safety are dealt with in the same way. If changes are likely to affect compliance, further tests should be undertaken before a product is released to the market. Any product may be packaged and branded a number of different ways, even though the physical and electrical characteristics may be identical in all cases. In this scenario, one set of Test Reports can cover all the products, although each would require an individual Telepermit with a one-one correspondence between the Telepermit number and Product name/importer. Software changes also potentially impact on compliance. Our approach is that having confirmed the first version meets our requirements, we expect suppliers to ensure that later changes do not cause problems. We do not require Telepermit holders to report every detailed change, but we do expect suppliers to check out a new batch of an existing Telepermitted product to make sure there are no unforeseen operating problems before releasing the new batch to the market. In all scenarios, it is important that any firmware/software changes which may affect compliance are checked by the Telepermit Holder. Hardware changes should always be re-tested. Software/firmware changes which do affect operation can push huge costs onto ISPs and Network Operators, as any problems actually caused by CPE are inevitably reported to them rather than the CPE vendor as a first move. Software can often be a complicating factor in that provision may be made for a user to "customise" the product features. A good example of this is the auto dialling features of a modem. It is not practicable for either Telecom or the product supplier to be responsible for some user settings. As a result, we have to rely on the user taking a common-sense attitude towards such issues. This is why we require suppliers to include supplementary information on re-dialling in User Manuals. These provide guidance so that we at least minimise overloading of our exchange equipment should an ISP "fall over" and its users then "attack dial" to recover their internet sessions. Should a customer ignore this information or any conditions attached to the Telepermit and published in the User Manual, Telecom reserves the right to take appropriate action with that customer. 3. TELEPERMIT RESERVATIONS We have had a considerable amount of trouble with Telepermit reservations due to the numerous changes that can take place after the initial reservation has been made. Typically, the marketing name or designation may be changed, resulting in the need for new label artwork and record up-dates. Another more serious problem is that products sometimes turn out to be quite different to what was described at the reservation stage. The net result is that we have to re-do a lot of work and the supplier has to re-label products after they have been assembled and packed. All this loses any benefit of obtaining a reservation in the first place. All in all, our preference is to withdraw the "reservation scheme". It was originally set up to provide for suppliers who had not allowed much time for testing and Telepermit processing in their marketing plans. We agreed to implement the service, especially during periods when other commitments meant that we could not process Telepermit applications within the usual 3 weeks we allow after receipt of the complete set of submission documents. For those suppliers continuing to request Telepermit reservations, we will now require full descriptions of the product and its features, and the usual set of photographs. For more complicated systems using multiple products, we will also require block diagrams of the relationships between the various components. For analogue products, pre-application testing should at least cover the RN so that the correct value can be marked on the label artwork. 4. V.92 MODEM REQUIREMENTS Further to the article in Newsletter No. 131 on V.92 modem operation, we are happy to accept V.92 modems for Telepermitting on the basis that the measured power levels of the up-channel at 48kbit/s comply with the TBR21 transmission level mask in lieu of PTC200, clause 4.2. It is difficult to measure this power level in New Zealand at present, as a modem will not implement the PCM transmission mode without an associated network/ISP modem to talk to. Even where ISP's install V.92 capability, a real connection is likely to run at lower than 48k, so such measurements would not be valid. Where V.92 modem suppliers submit overseas test reports, a block schematic for the test set up for the plots should also be submitted. Such results will generally be acceptable for Telepermitting purposes, as long as they are equivalent to the PTC 200 test set-up. We will consider such overseas test reports at least until we have independent test laboratory capability in New Zealand . V.92 is currently being associated with a quick start handshake, provision for Modem on Hold (suspend and resume the internet session), and a higher up-load speed. However, any specific modem does not necessarily have to offer all of these features. The "modem on hold" (MOH ) function is dependent on the modem being able to recognise the call waiting signal and indicate to the user that a call is waiting. However, the equipment used by the network and ISP has to support the "on-hold" for it to work correctly. This situation shall be clearly advised to the prospective purchaser and be included in the User Manual. While it can be expected that suppliers of new V.92 modems in New Zealand will go through the proposed Telepermit test procedure, there is also the possibility that some V.90 products will be software upgradeable by customers. While such action is outside the control of the original supplier, it is recommended that Telepermit holders seek the co-operation of their manufacturers in making sure that websites used for downloads publish a suitable warning regarding the need for the ISP and network concerned to support the new features. Needless to say, we do not want customers complaining that their newly up-graded modems do not work as they expected. In summary, it is proposed that additional requirements for Telepermitting V.92 modems will be covered in a new clause 11.5 to Specification PTC 200. The details are shown in Appendix No. 1 to this Newsletter. Industry comment is invited on the draft clause. 5. CALL WAITING FUNCTION Detection of the Call Waiting signal is not restricted to V.92 modems. Any add-on device could well perform this function, which would be to: a. recognize the call waiting signal (400 Hz "on" for 200 ms, "off" for 3 sec, repeated three times, then 200ms "on"), and b. indicate to the user that a call is waiting. Even if neither a modem nor the customer's ISP is V.92 capable, the call waiting function should still work to the extent that the user can take the voice call by terminating the Internet session. From a Telepermitting point of view the only "output" to the network would be the Switch-Hook-Flash (SHF) needed to transfer to the voice call. The SHF can be performed by the telephone. For example, the phone may go off-hook in parallel with the modem, after which the modem goes on-hook, and the phone performs the SHF. In fact, this would seem preferable, as the other caller would not be connected to a modem for a short period. For the integrity of the Telepermit system it is desirable that the ability of a modem (or any other add-on device intended for this purpose) to detect the call waiting tone is tested and confirmed satisfactory. The duration of the SHF, if implemented by the modem, would require testing to clause 6.8 of PTC200 in any case. The requirements are clarified in Appendix No. 1 as a new clause 11.6 to PTC 200. Industry comment is invited on the draft clauses. In due course, a formal amendment will be published to PTC 200. In the meantime, the above conditions are to be applied by Access Standards and its accredited test laboratories as an interim arrangement for dealing with V.92 products. 6. PTC 200 AND TNA 102 NOW ON-LINE PTC 200 and TNA 102 (pdf), our two most commonly used specifications, are now published free of charge on-line. This move is preparatory to an overall revision, which has been under consideration for some time. 7. ACCESS STANDARDS STAFFING CHANGES Following Anna's departure, we will be getting only part-time assistance on our "procedural matters" and will no longer have a clerical assistant sitting with the group. As a result, one or other of the technical team will handle general enquiries on Telepermit matters. For those companies enquiring about Telepermits that have already been granted or following up enquiries made by one of the team, any further enquiries or responses should preferably be addressed to that particular team member. We will continue to "cover" each other during staff absences, but it will assist us in giving prompt replies if any enquiries are dealt with by the person handling a particular application or product DOUG BURRUS Manager Access Standards ACCESS STANDARDS NEWSLETTER No. 132: APPENDIX No. 1 The following clauses are proposed as amendments to PTC 200. Industry comment is invited prior to their being formally published. In the meantime, compliance with these requirements will be accepted by Telecom for Telepermit purposes. 11.5 V.92 Operation (1) Suppliers of V.92 capable modems intended to be offered for sale as such shall submit the following additional information for Telepermit purposes:- (a) spectral plots for V.92 operation; and (b) diagram of the test setup for obtaining these plots; and (c) confirmation that the modems can respond to the NZ call waiting tones; and (d) a description of how the modem implements the MOH function. e.g. a flow chart or state diagram of events; and (e) SHF timing (if applicable); and (f) a clear written warning to the customer that the additional features are only available if the ISP and its associated network equipment also has the necessary capability. This should be at the point of sale and on the outside of the modem packing so that there is no presumption by the prospective customer that these features will work unconditionally. (2) Where new V.90 modems are being submitted for Telepermit and these are claimed by the supplier as capable of being upgraded by the customer subsequently loading software for V.92 operation, before making the V.92 software available, the supplier shall:- (a) ensure that the software provided does support all of the features claimed for it; and (b) submit the information listed in (a) to (f) above; and (c) ensure that customers are provided with clear instructions on how any new features are to be operated. (3) Where the driver software of a previously sold V.90 modem may be up-graded by the customer to V.92 operation, even though no claims were made to this effect at the time of the sale, it is recommended that the Telepermit holders concerned make clear to their customers whether or not that new software has been confirmed to operate as claimed. * It is appreciated that neither the software concerned nor its suitability are always under the control of the Telepermit holder. Nevertheless, Telecom expects the Telepermit holder to support the product as far as is practicable, to be aware of any software available for its product, and to take appropriate steps if there is a known deficiency in that software when used on the Telecom network." (4) For the avoidance of doubt, all other relevant clauses of PTC 200 apply to V.92 modems, as for any other type of analogue line modem. 11.6 Call Waiting detection Any device claimed to provide detection of Telecom's Call Waiting signal shall be tested to confirm that it will reliably detect that signal (see TNA 102, clause 7.1 for details) under the full range of likely service conditions. These include: a. the 400 Hz nominal frequency, at the published cadence, with signal level set at -15 dBm; and b. the 400 Hz nominal frequency, at the published cadence, with signal level set at -25 dBm; and * While TNA 102 provides for tolerances on both frequency and cadence for some supervisory tones, Call Waiting tone is accurately generated by the network and faithfully transmitted by access systems, with insignificant timing or frequency changes. In view of this, testing at varying frequencies and cadences is not required.