TELECOM ACCESS STANDARDS NEWSLETTER NO. 137

DECEMBER 2002

CONTENTS
1. AMENDMENTS TO PTC 200 AND TNA 102
2. V.92 TESTING PROCESS
3. PRIVATELY-IMPORTED CDMA (027) HANDSETS: TELEPERMIT ISSUES
4. RESIDENTIAL-TYPE PREMISES WIRING: PTC 103 Amendment No. 1.
5. AMENDED TEST REQUIREMENTS FOR ADSL LINE FILTERS
6. USE OF THE SAME MODEM "MODULE" IN DIFFERENT MOTHERBOARDS
7. NEWSLETTER COPYRIGHT
8. ON-LINE PUBLICATIONS
9. SEASONS GREETINGS
RETURN TO MAIN INDEX




1. TELECOM NETWORK SUPPORT FOR V.92 OPERATION

1. AMENDMENTS TO PTC 200 AND TNA 102

From time to time we have outlined the need for changes to these two key specifications in these newsletters, but not actually amended the specifications themselves. Completely revising these documents is a major task and we have been concerned that piecemeal amendments could imply that any given change is complete.

Rather than continue to leave the actual specifications out of date, we are going to take advantage of their being published on-line and make the formal the amendments progressively. The first steps are to pick up the various changes announced in these Newsletters and we will get this project under way early in 2003.

Telecom is currently working on its Next Generation Network and Access Standards is working with other parties in Telecom to determine just whether there will be any changes that will impact on existing in-service CPE and current Telepermitted products being offered for sale. Advice on such matters will be announced in these Newsletters from time to time, along with any resultant amendments to our PTC specifications.




2. V.92 TESTING PROCESS

In Newsletter No. 136, I mentioned that we might have to insist on a mandatory local test to supplement overseas PTC 200 test reports for V.92 modems. There may be overseas test laboratories who are willing to set up a "Telecom NZ PSTN simulator such that they could carry out such tests.

My comment was based on the assumption that such a simulator would not be an attractive business proposition for an overseas test laboratory in view of the few tests that would probably be needed. However, should an overseas laboratory wish to invest in such equipment, we are willing to consider any applications for accreditation to carry out these tests.




3. PRIVATELY-IMPORTED CDMA (027) HANDSETS: TELEPERMIT ISSUES

WARNING!!

Some CDMA handsets available overseas may seem cheaper or a whole lot more "up-market", but PLEASE DO NOT purchase a cdma handset while overseas and bring it back to New Zealand.

If you are reading this on-line information from an overseas country, and you are a current cdma user about to return to New Zealand, we recommend that you sell your handset in your present country, where it will have maximum resale value.

The following gives further background information on just why this warning is being published:-

International Roamers vs Local Customers
We are receiving a number of enquiries on this issue. It is probably complicated by the point that we and overseas cdma operators are promoting international roaming and thereby allowing customers to connect overseas handsets on a temporary basis. It seems illogical that we do not Telepermit the same handsets should a customer wish to connect them permanently to our cdma network.

While cdma is reasonably well standardised, there are differences between networks around the world. These may arise because of different network equipment manufacturers or because different operators provide a different range of services; cdma handsets are thus provided with specific internal software for each network. Even though the software varies, the manufacturer may use the same model numbers to describe the handsets made for different markets.

Roamers remain the customers of their home network. Telecom has an agreement with that network to allow such customers to connect here on a temporary basis and that connection is based on the continued use of the overseas number. The customer is able to connect in most cases for making and receiving basic calls via our cdma network, but no assurances are given as to the ability to make/receive calls, nor as to the user's ability to use data services.

To give such guarantees, it is necessary to test all facets of the handset for compatibility with the particular network to which it is to be connected. Telecom is currently spending some weeks to thoroughly test each new model of handset, and develop software changes with the supplier. The resulting product gains a Telepermit and Telecom can then give fairly firm assurances that it will support the network services it claims to support.


Testing costs
Some readers have seen the CDMA Telepermit Application Form on our website and asked about getting an individual handset Telepermitted.

As can be appreciated from the time involved, the cost of this testing is many thousands of dollars, not counting the cost of software changes developed and loaded by the manufacturer. Needless to say, it would neither be practicable nor economic to carry out such an extensive test programme on individual phones.

The whole programme of testing is intended to cover local importers bringing in several thousand units of the same model, thus justifying the cost of the testing, software development, and Telepermit approval.

Even for high value overseas handsets, the lowest cost solution is to purchase a local replacement.

"Apparent" calling ability
A complication is that, even without a roaming agreement in place, any customer with an overseas cdma phone may be able to make a call to *123, or to 111, 911 (and other recognised emergency numbers, such as 112, 000, although not all such calls may reach our emergency services). Any number pre-programmed into the handset as an emergency number could generate a call, independent of the actual emergency numbers used in this country.

This gives the mistaken impression that the phone should be able to be connected here on a permanent basis.

Converting overseas handsets
For those models used here, we obviously have access to a "NZ software load". With this in mind, Telecom was hoping to set up facilities for replacing the original software in handsets of the same models imported privately by customers. This service would have been restricted to those particular models which we have Telepermitted, of course. As such, it still would not have covered the vast range of models available overseas.

Unfortunately, fraudulent purchases of subsidised handsets by people signing up for long term contracts, then going overseas and ignoring their service contract obligations, have been rife in recent years. Mobile service providers worldwide have thus been protecting their interests by arranging for the manufacturer to provide security coding specific to the handsets they have subsidised. This Software Protection Code (SPC) prevents a handset being re-programmed by other than the original service provider.

As a result of this security provision, we are unable to re-load an overseas handset with local software. Unfortunately, this means that we have to decline to convert or connect handsets brought into New Zealand by local residents returning from overseas or those immigrating here, even though we appreciate that they are our prospective customers.




4. RESIDENTIAL-TYPE PREMISES WIRING: PTC 103.

Newsletter No. 114 announced that we would be publishing Amendment No 1 to our Code of Practice to cover safety requirements in relation to the segregation of telephone wiring from Low Voltage (230 v) cabling. Unfortunately, there were other issues under consideration at that time and this amendment was not published.

To clarify the points agreed during negotiations with Energy Safety to replace and elaborate on the traditional requirement of "permanent separation of at least 50mm":

* "Permanent" separation requires both classes of cables to be fixed in position. This is obviously impracticable in inaccessible spaces, such as wall cavities, where it is neither possible nor permissible to clip cables in position. Within such inaccessible spaces it is possible that phone cables may touch power cables. This is permissible provided that:

* neither cable is fixed in position, and

* both classes of cable are fully sheathed.

Where the cables are not clipped in position, they are free to move at any point where they are touching and there should be minimal risk of "cold flow" of the insulation. To meet the second requirement, any unsheathed phone wires connected at jackpoints and terminating boxes must NOT protrude into the wall cavity or any other space also occupied by Low Voltage cables. Unsheathed phone wires must be contained within a substantially enclosed mounting box.

* When carrying out telephone wiring on a finished wall, even where 230 V cabling is detected within the wall cavity, it is not known whether any of it is unsheathed. To avoid any risk of unsheathed power conductors touching either sheathed or unsheathed telephone cable, any jackpoint or box for telephone terminations is required to have a horizontal separation from electrical outlets, switches, etc, on either side of the wall of at least 200mm..

* Where the two classes of cable are accessible, they must either be separated by fixed and continuous barriers, or be fixed in position to maintain a separation of at least 50 mm.

Safety is not the only criterion, of course. While it might be "safe", the usual minimum separation of 50mm risks interference by induction if there are long lengths of both classes of cable run in close proximity to one another. Clause 2.3.3 (4) of PTC 103 addresses this issue by requiring that there shall be no more than 3 m of power and telephone cabling run in parallel when the minimum spacing of 50 mm applies. The basic principle is to keep the two classes of cable separated as far as practicable.




5. AMENDED TEST REQUIREMENTS FOR ADSL LINE FILTERS

When we initially introduced "JetStream", Telecom planned to provide the service only at our latest NEAX 61-E exchanges. A later development would extend the service to customers connected via street cabinets. Both cases limited the maximum DC line current to about 80mA. Accordingly, PTC280, which specifies Telecom requirements for the plug-in line filters used for self install, specified correct operation for DC line current only up to 80mA.

Our earlier NEAX 61-Kai switches, which can supply in excess of 100mA DC line current to very short lines, were expected to be retired before they would be equipped for JetStream. Notwithstanding the original plan, as a result of Telecom's moves to extend the coverage of JetStream services, it now being provided at these earlier exchanges. There has already been at least one known service-affecting case where the filter inductors have been saturated by excessive DC current.

The effect of saturation is to lower the data speed when any voice CPE connected via that line filter goes off-hook. In more extreme cases, the JetStream service could lose synchronisation. Where there is insufficient current capacity, the filter's performance is reduced. An audible hissing sound from demodulation of the insufficiently attenuated JetStream signal may also be heard on the associated phone.

To avoid, or at least minimise problems where customers are fitting line filters on these higher current lines, we have asked testing laboratories to test all new designs of filters with up to 100mA DC. PTC 280, clauses A1.2(1) and A2.2(1), currently specifies only 80 mA. This will be amended in due course.

It is suggested that those suppliers who have already been granted Telepermits for line filters should have them re-tested at 100 mA. For those existing types that cannot meet PTC280 requirements with 100mA DC, the product user instructions will need to be expanded with a suitable warning.

In those cases where line current exceeds the rating of the line filters, the customer should either use different filters capable of the higher current operation, or ask for Telecom to install a splitter at the line entry point. The standard installation charge applies.




6. USE OF THE SAME MODEM "MODULE" IN DIFFERENT MOTHERBOARDS

Newsletter No. 115 raised the issue of Audio Codec and Audio Modem Riser (AMR) cards and how we would handle their Telepermitting. This technology has since evolved to "CNR" - Communications and Networking Riser. This technology supports V.90 modems, multi-channel audio, telephone line-based networking and 10/100 ethernet based networking. Like AMR, it takes advantage of the spare capacity provided by today's high speed CPU's to carry out digital signal processing. The CNR modem can then act as the Codec.

As the result of these technologies, analogue modems are getting smaller and smaller; one manufacturer recently claiming to have got them down to a 27 mm square area on a doubled sided 4 layer printed circuit board. Such small modems can be either connected as a daughter card on a whole range of different motherboards or copied and pasted within the motherboards themsleves. In the latter case, the modem chipset designer can produce a standard "circuit module" for use with any manufacturers' motherboards. Exactly the same module may be used on a wide range of different motherboards.

Given that the module and its driver software has been shown to meet Telepermit requirements, the question arises as to how best to Telepermit what are now essentially motherboards, as distinct from just modems. Obviously, it would be pointless for us to insist that every mother board be tested in these circumstances.

The most practical approach is to Telepermit the "modem module" as an entity in its own right. One party (such as the module design company's representative in New Zealand) would submit test reports of the modem performance and photographs in the usual way to obtain a preliminary Telepermit, possibly (but not necessarily), based on tests carried out on a particular family of motherboards made by one of the computer manufacturers concerned. The standard NZ$300 plus GST fee will apply and the permit label would show that party's designation for the modem module. That party would then have the assurance that the product has met Telecom requirements and then be able to authorise other computer manufacturers to make use of the test reports and preliminary approval to gain their own Telepermits.

A company representing the holder of the design rights is probably the most appropriate to arrange the preliminary Telepermit, as this would avoid the situation where an individual computer or motherboard manufacturer is being asked to authorise a direct competitor to make use of the test reports.

Because of the legal process behind our Telepermit system, each computer supplier making use of the module concerned would be responsible for ensuring that it still complies with our network requirements. For this reason, they would apply for their own Telepermit, sign the undertaking on the Application form, and provide authorisation by the holder of the preliminary Telepermit to use that party's intellectual property (namely the test reports and preliminary approval). A colour photograph of the modem module section of the motherboard and formal declaration that the driver software is compliant is also to be supplied to Access Standards as evidence that the module is identical, as claimed.

In all cases, the computer manufacturer would be responsible for the EMC and overall safety compliance of the computer, based on the safety compliance of the motherboard. Each motherboard will have to provide all the necessary clearances around the modem TNV3 line interfaces in the usual way.

A single NZ$300 plus GST fee (our standard fee) will apply to each computer manufacturer using the modem module within its range of products, independent of the number of motherboard variants and computer models within that range.

With the arrangement described, the computer manufacturer's own Telepermit number would be shown in any convenient position on the outside of the computer case to indicate that it can be connected to Telecom's network.




7. NEWSLETTER COPYRIGHT

It might be timely to remind readers that these Newsletters are "copyright free" in the sense that we have no objections to the text being passed on to other parties or used in full or in part in company publications, etc.

The whole aim of these Newsletters is to define and explain Telecom's requirements with respect to CPE. Any assistance other parties can give in "spreading this news" is greatly appreciated.




8. ON-LINE PUBLICATIONS

This year has seen us convert very largely to on-line publications of PTC and TNA Specifications, as well as for these Newsletters and other miscellaneous publications. This has avoided our charging for specifications and doing a lot of associated accounting work, but it has also had another quite surprising impact on our work.

The company providing our server sends us regular usage reports and we have been watching a gradual increase in both the numbers of enquiries and the number of "pages" being downloaded. Our website is now getting some 10 000 successful "page requests" each week, spread fairly evenly across 24 hours every day of the week, indicating a worldwide readership. Weekly downloads are hovering around 100 MB, (November downloads amounted to 567 MB), which represents quite a lot of paper, printing and postage costs considering that the majority of our site content is just text.

We have covered quite a wide range of subjects during the year in an effort to keep the CPE industry up to date with developments, how we propose to handle new issues, etc. It is very much a case of dealing with issues as they arise, so the topics change from issue to issue.

We have retained our policy of "keeping it simple" and avoiding the high tech frills seen on so many websites these days. We are aiming to inform, not impress, and hope most of our readers are finding this the best approach.

2003 is expected to see the outcomes of Telecom's Partnership with Alcatel and we will do our best to give early warning of any network interface changes that might affect in-service or new CPE products.

We do not expect any really significant changes to the "POTS interface" at this stage, but (as advised in earlier Newsletters) some of the legacy provisions, such as decadic dialling, earth start for PABX systems, etc, will almost certainly not be supported by our new generation network equipment.




9. SEASONS GREETINGS

The end of December has come around once again and our little team of three, Richard Brent, Alan Reedy and I, are getting tidied up for the summer break. For those readers in the Northern Hemisphere, our condolences over your cold weather and dark nights, but we did have our turn around six months ago.

We wish all our readers and Telepermit holders a Happy Christmas and a successful 2003 (despite any weather problems).






DOUG BURRUS
Manager
Access Standards