Ringing in the new: VoIP telephony

Theresa Fox

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CityU staff based in Festival Walk will soon have a new communication tool on their desks: an IP phone handset. In a pilot scheme scheduled to be implemented in August or September, 300 staff members will try out the new technology before the digital system is installed on the main campus.

The Director of Computing Services, Mr K H Poon, gave Linkage the background to the decision to change the way we talk to each other.

Our current telephone system consists of two parts, Mr Poon explained. There's the telephone company, which runs the district and metropolitan switching, and the enterprise: the Private Automatic Branch Exchange (PABX). The PABX has two functions: to provide the connection between two parties on campus, and to connect the users to the city link systemNin our case, PCCW's Citinet services. Although the PABX system is efficient, its major disadvantage is that its circuit switching is an analogue system.

Circuit switching has been used by telephone networks for over 100 years. In this system, when a call is made between two parties, a dedicated connection is maintained for the duration of the call. However, since the volume of traffic for voice is only a small percent of the capacity off the cable, much of the bandwidth is wasted.

Voice-over Internet Protocol (VoIP) technology was introduced in the mid 1990s. VoIP enables the two-way transmission of digitized voice traffic over a data network, using a method called packet switching. Internet users could make voice calls between specially equipped PCs, or between a phone and a specially equipped PC. Back then, the system, although usable, could not match PABX for quality. "In the early days, the voice quality was poor because when the data traffic was heavy, the network jammed and voice data traffic was blocked. There were strange noises or sudden interruptions," Mr Poon said. Today though, if there is heavy traffic voice data is given priority and only data is jammed. Quality of service is assured.

Phasing out PABX

With VoIP becoming increasingly popular, the PABX companies have seen the writing on the wall and are all producing IP phones. "It's inevitable that the old PABX market will be phased out," Mr Poon said. "It may be sooner than we expect because most of the companies have decided not to produce or develop the PABX system and have focused on the IP phone as the company product."

There are several reasons for this change of focus, Mr Poon explained, not the least of which is the much lower running cost. "Although the initial set-up cost is more or less the same as for a PABX system, we're talking about running costs which are one-tenth or one-eighth of the old system. This is because it's simple, it's just a computer, not a huge PABX system." And, of course, because it runs on a data network, anywhere you have the network, you can attach the phone. Yet another advantage is that you don't need an expensive separate cabling plan for the enterprise. The computer cable will go from the wall socket into the phone, which will act as a switch. A further cable will connect the phone to the computer.

The IP phone looks very similar to a normal phone but because it's connected to the computer, it will be smarter than our current handsets. It will perform all the functions we have come to expect but will also have a bigger screen for displaying e-mail, images or video and can be used for video- and voice-conferencing. And because it's a computer, we'll be able to access the telephone directory without flicking through the familiar white book. There's even a product, not yet on the market, that will be able to read our e-mail to us. So, even if we have to initially sacrifice a bit of voice quality, IP has a lot of advantages.

CityU's first IP phones will be installed in the student hostels in June. "When we first started planning the hostels two years ago, we decided to go for IP phones," Mr Poon explained. "It was early in the development, and some people were worried, but we made a bold decision. And once weOd decided not to install PABX cabling, there was no going back."

Each room in the hostel will have two computer ports and one simple model IP phone. The hostel management office will provide basic support to the student phone users, with the Computing Services Centre (CSC) providing technical backup.

Pilot scheme for Festival Walk staff

Meanwhile, CityU staff based in Festival Walk are looking forward to being the guinea pigs for the campus version of the IP phone system. The pilot scheme will be introduced there because there are around 300 city lines going to the telephone company's switchboard, for which the University pays around $200 per line per month. "It's quite expensive because they are business lines and are charged more for each additional function, not to mention that we can't communicate with the main campus internally. And there's the question of scaleN300 is just the right size," Mr Poon said. Changing to the IP phone at Festival Walk will cost the equivalent of 30 months" rental of Citinet services and the University will end up with its own system.

The tender is through and the orders have been issued but the suppliers have an urgent job to complete firstNthe CityU hostels. By August or September though, each CityU staff member in Festival Walk will have an IP phoneNand a new phone number. That is inevitable, said Mr Poon, because the IP phones and the old analogue phones are connected to different switching stations at the telephone company. At this stage, it looks as thought the first five digits of the number will change but the last three will stay the same. "We'll let everyone know in advance, once the new numbers are finalized, so that they can go ahead and get new cards printed," Mr Poon said. "And the telephone company will advise callers of the changed numbers for at least two months."

And for staff a bit worried about learning how to use the new device, the old phones will be around for the first two weeks or so to make sure everyone has time to learn how to use the IP phone. CSC will provide an instruction booklet and also run some briefing sessions. "We may even set up demo phones first, so that people can come and try them out," Mr Poon said.

Main campus a complicated exercise

After the pilot scheme has run for two or three months, planning will start for the main campusNa more complicated exercise because of the existing PABX system. But the main complication, Mr Poon said, is that we are planning to change over the systems without changing to new phone numbers. "We haven't received the final figure from the Facilities Management Office yet but it seems we have around 5,000 phones on the main campus. Because of the number, PCCW have agreed to move the whole lot into a new station, so we'll try to keep the old phone numbers."

And with 5,000 phones, it will be impossible to change over in one go. "If we do it in phases, during the transition period, with half of our people on the old system and half on the new, how will they communicate? That's a challenge!"

There are several possible solutions to the problem and there is time to consider them all, Mr Poon said. The Budget Committee has allocated funds and the FM" has agreed that CSC will take over the control of the PABX system on 1 July. "The transition won't be easy, it's a complicated exercise and we have to collect more data and consider the difficulties before we make our decision. But the day will come when we install IP phones for everyone at CityU and the old phone system will be history."


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