CONTENTS
1. NETWORK NUMBERING ISSUES - IMPACT ON PABX SYSTEMS AND PAYPHONES
2. TOLL TARIFF DATA
3. EQUIPMENT CONNECTED TO CELLPHONES
4. TWO-WIRING INTRODUCTION
5. PTC 223: CHANGES TO DRAFT AND CLOSE OF PUBLIC COMMENTS PERIOD
6. SOHO WIRING STANDARD
7. TRANS-TASMAN MUTUAL RECOGNITION ARRANGEMENT
8. USE OF LOW BIT RATE VOICE TRANSMISSION SYSTEMS
9. CORRECTABLE TELEPHONES?
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1. NETWORK NUMBERING ISSUES - IMPACT ON PABX SYSTEMS AND PAYPHONES
Telecom is planning to extend the "012x" number range, which is currently used for Telecom Calling Card calls.
As with Calling card calls, all of the proposed "012x" services are charged to the caller or to a third-party, NOT to the calling line. In view of this, it is preferred that these calls be supported by all PABX systems, payphones, etc. They certainly do not NEED to be toll-barred.
The new codes are being implemented progressively from October 1996. They are the 4-digit codes "0124" and "0125", plus the 7-digit code "0127XXX". On dialling these codes, callers will be prompted to enter their Card Number, PIN and destination number.
Further details on the services will be announced in due course. In the meantime, it is suggested that PABX and payphone maintainers seek their customers' agreement to "open" these codes in the systems they are responsible for. This will avoid a last minute rush to reprogramme systems when the services come into operation.
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2. TOLL TARIFF DATA
Recent enquiries from Call Detail Processor (CDP) and payphone suppliers have raised the point that Telecom changed its arrangements for supplying and regularly up-dating toll charging tariff data for these applications. This change took place some time back. The quarterly publication "Call Charging Steps and Network Numbering" is still available in both paper and soft copy format from Access Standards. This can be used to format the charging data for a CDP, noting that the relationship between call charges and digits dialled will vary according to the Telecom charging area in which the CDP is located. Such formatted data is no longer supplied directly by Telecom.
Regular up-dates of changes to numbering and charging are now passed to an outside contractor, who is able to undertake software design and maintenance on behalf of CDP suppliers and users. This company, DS Squared Ltd, can be contacted in Auckland on (09) 535 7149 or at Wellington on (04) 472 5861. The necessary up-date information is provided "as it happens", rather than as a quarterly summary.
Readers wishing to get more information on the services provided and their costs are advised to contact this company.
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3. EQUIPMENT CONNECTED TO CELLPHONES
Section 6 of the Telecommunications Act 1987 states that "No person shall, without the agreement of the network operator, connect any additional line, apparatus, or equipment to any part of a network or to any line, apparatus, or equipment connected to any part of a network owned by that operator". This Section of the Act is the basis of Telecom's Telepermit system.
There is increasing use of cellphones as the access path for add-on equipment providing data and other services. This is especially the case for mobile applications, such as the portable office, and for network access in remote locations, such as for telemetry applications in river management, reservoir control , etc.
It appears that some suppliers of these add-on devices have NOT considered the need to gain a Telepermit for their products. However, this is necessary in all cases where the add-on device is generating signals that are passed in to the cellular network. Whatever signal is produced by the add-on equipment is usually connected through to the PSTN, so it is important that signal and transmission levels generated by the add-on and the associated cellphone are also kept within the limits defined by PTC 200 when measured within the telephone network.
Unfortunately, there is no overall accepted standard for the interface between cellphones and any add-on equipment. That this applies to the physical connection is obvious from a brief inspection of the various makes available on the local market. What is not so obvious is that the lack of a uniform standard also applies to the electrical interface.
Another potential problem is the generation of excessive electromagnetic interference where integrating a cellphone with an add-on product into a single unit involves removal or disruption of the original cellphone RF screening. This could lead to breach of the Radiocommunications (Radio) Regulations.
To avoid any problems, suppliers of add-on equipment for cellphones are required to liaise with the cellphone manufacturers or their local agents to determine the interface specifications of the various makes and models of cellphone. In addition, those add-ons will need to be checked over by our cellular engineering group to confirm that they do work as intended with the selected makes or models of cellphone. The contact person is Simon Cooke-Willis, Manager Industrial Support. He can be reached by telephone on (04)802 9835 and (025) 421 657, or by fax on (04) 384 4009.
Where they have been shown to meet the relevant regulations and comply with PTC specifications as regards the signal levels transmitted into the cellular network and PSTN, Telepermits will be issued for each add-on unit, stating the various models of cellphone with which they may be used.
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4. TWO-WIRING INTRODUCTION
Telecom's supplies of 2-wire jackpoints are close to hand and we will soon be starting the conversion programme as part of our regular residential wiring maintenance procedures. When visiting residential customers' premises to investigate a fault, Telecom repair staff may take the opportunity to replace the earlier 3-wire jackpoints. Needless to say, with around 4 million 3-wire jackpoints estimated to be in service nationwide - not all of these in residential customers premises, of course - it will take quite a few years to complete the conversion.
Non-Telecom suppliers are showing interest in making the new 2-wire versions and we will encourage their use by all customers at the earliest practicable time. Telecom certainly does not want to be put in the position of replacing newly-installed 3-wire jackpoints, so the quicker all customers can have access to the new versions, the quicker we will improve service reliability.
If jackpoints are to be added to existing 3-wire systems, full conversion to 2-wiring is our recommended course of action.
One important point that must be stressed is that customers should NOT add to 2-wire systems using the earlier 3-wire designs. This causes wiring complications and loses the benefits of improved line balance, which is particularly desirable on lines subject to electrical noise or those used by customers for data transmission.
A major feature of the 2-wiring conversion and the related RAL reassessment scheme is to improve ringing performance where multiple devices are connected to the same line. Pending 2-wire conversion, it is recommended that residential customers with old-model fixed 1000 ý bellsets have them removed or replaced to avoid ringing problems with modern electronic equipment. Typical replacements are a small plug-in electronic ringer or bell, or a modern 2-wire connected 4000 ý bellset. Many old bellsets have been in place for years and years and there is no longer any real need to retain them. In such cases, the customers concerned may be happier to have a jackpoint fitted and replace the old bellset with a modern telephone at little extra cost.
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5. PTC 223: CHANGES TO DRAFT AND CLOSE OF PUBLIC COMMENTS PERIOD
We are about to finalise the public comment draft of PTC 223, which was issued in June. So far, the only substantial changes are that the capacitor tolerance is now to be ± 10%, not ±20% as in the draft, and the warranty provisions are being relaxed from those proposed in the draft.
The capacitor change relates to our investigations into ringing performance and RAL assessment. We have found that if the entire tolerance range of ± 20% capacitors is taken into account, the expected current sharing of 3-wire CPE devices connected in parallel can be changed by a full RAL number. Tightening up the tolerance will result in much better load sharing so that customers can place more reliance on the "New RAL number" when it comes into force. This will be quoted on the Telepermit labels of those products tested in accordance with the new measurement scheme, which is currently under investigation.
The draft originally required the provision of space on the Telepermit label on which the installer could mark the installation date. Telecom is now proposing to simply mark the month and year of installation on the inner surface of the faceplate. For example, "9/96" for September 1996. Where the Telepermit label can incorporate space for an installation date without too much difficulty, this is still the preferred option. However, it is not now a mandatory requirement for Telepermit, as it is not feasible on some product designs.
Jackpoint suppliers are asked to submit any further comments on the draft by 14 September.
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6. SOHO WIRING STANDARD<./A>
The new SOHO wiring standard, developed by the joint Australia/New Zealand Building Cabling Standards working group, is now with the printer and should be published in the next month or two. I will cover the pricing and availability in a later Newsletter.
SOHO will NOT be adopted as the new Telecom wiring standard, as our own new 2-wiring scheme is adequate for the great majority of residential and small business customers, who need only telephony and low speed data services. Our new 2-wiring scheme is far simpler to install and, above all, it is far cheaper.
Nevertheless, for those customers who want flexibility of provision, high speed data and LAN facilities, a SOHO installation offers the performance of the latest generic building cabling systems, without the full complexity of the new commercial building cabling standard, AS/NZS 3080: 1996.
SOHO cabling is based on the use of Cat 5 Unscreened Twisted Pair (UTP) cable, with performance potentially up to 100 MHz. As such, it should meet all currently foreseen requirements. As with the larger generic cabling systems, SOHO uses "star" wiring, but with a relatively simple cross-connect frame and test disconnection feature. "RJ 45" 8-way modular jackpoints are used as the Telecommunications Outlets (TO's).
It is expected that local hardware suppliers will be making the necessary parts available and producing basic installation kits for those homeowners who wish to undertake their own SOHO installations.
7. TRANS-TASMAN MUTUAL RECOGNITION ARRANGEMENT
Recent publicity about the Trans-Tasman Mutual Recognition Arrangement Bill, which is going through Parliament, has given rise to some concern by CPE suppliers. Reports in the news media mentioned that telecommunications terminal equipment (usually referred to in inter-Government negotiations as "TTE") is included in the free trade arrangements. This is quite correct. What was not mentioned in the brief news reports is that this is no real change from the present situation in that anyone now can import or export TTE.
Notwithstanding the "free trade" issue, any harmonisation of standards, and the mutual recognition of test reports, it will still be necessary for TTE (CPE in NZ, or Customer Equipment, "CE", as it is termed in Australia) to obtain the necessary permits for direct and indirect connection to public networks. Thus, neither AUSTEL's permit requirements nor Telecom's Telepermit requirements are affected.
Further information on the Trans-Tasman Mutual Recognition Arrangement is available from the Ministry of Commerce (their contact person is Malcolm Alexander, who can be reached by phone on (04) 474 2819, or by fax on (04) 499 1791).
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8. USE OF LOW BIT RATE VOICE TRANSMISSION SYSTEMS
We have recently had a number of suppliers asking about the possibility of our further relaxing our requirements for the use of low bit rate voice transmission on calls involving the public network. Our approach to date has been to permit no more than 3.5 QDU's of quantisation distortion within a private network connecting calls to or terminating calls from the PSTN. This was originally based on the use of ITU ADPCM equipment over a PCM link connected between two analogue interfaces. Such equipment can be connected in tandem without further degradation due to distortion provided that there are no analogue conversions between the links, they are switched at 64 kbit/s and the whole link is synchronised.
There are NO restrictions by Telecom on how much reduced bit rate equipment is used on calls wholly within a private network.
Equipment for combining voice compression with ATM and Frame Relay is now coming available and, as stated above, there is no objection to this being used wholly within a private network, even at bit rates of around 6 Kbit/s. The basic principle behind Telecom's current position with regard to compression is that the person paying for the call decides on the balance between cost and quality of transmission. This has to be qualified for international calls because of the need to comply with ITU Recommendations for transmission quality. However, with current international tariffs being the same throughout the country, there is little point in using a private network to access the Telecom international exchange.
In view of this basic principle, calls incoming to a private network are a different proposition. Since the caller is usually paying for the call and expecting full "toll quality" transmission, we require the private network to keep within the 3.5 QDU limit. The private network is also required to provide any echo cancellation that might be needed to maintain call quality due to any excessive delays introduced by the terminating network.
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9. CORRECTABLE TELEPHONES?
International telephone number lengths will soon be increasing to as many as 15 digits. Add an "00" or "05xx" prefix, and even more digits to dial for calling card calls, and the probability of a dialling error gets fairly high. Why is it that telephones aren't made more user-friendly?
Memory dial phones are common, but suppliers don't seem to have considered the concept of providing displays AND a "backspace" button. If they did, customers would be able to key in the digits, check that they have the right number or make corrections, and then press the "Send" key like a cellphone. This could avoid a lot of frustration for the users and save a lot of "wrong numbers". Any offers?
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DOUG BURRUS
Manager
Access Standards
AUGUST/SEPTEMBER 1996
