Home » IT Services News » IT Services News No. 161. January - February 2013 » Message from the Director - Moving from PABX Systems to IP Phone Systems

Message from the Director - Moving from PABX Systems to IP Phone Systems

The University had been relying entirely on analog-based Private Automated Branch Exchange (PABX) systems for voice communication until 2011 when the first digital-based IP Phone system[1] was installed in the HKJC Building for Interdisciplinary Research.  Since then, additional IP Phone systems have been deployed with a total of around 1,800 phone lines covering the new Centennial Campus; the Residential Colleges at the Lung Wah Street; and a few areas in the Main Campus.    

As technology advances, there is a growing demand for a Unified Communications (UC) platform to integrate real-time communication services, such as telephony, video conferencing, instant messaging and presence information, with non-real-time communication services, such as voicemail, e-mail, Short Messages Service (SMS) and fax. 

Today, the University still has around 5,000 PABX lines.  Voice communication is a pillar of UC; unless it becomes digital-based, implementation of UC in the University is undoubtedly handicapped. There are several issues with the PABX systems in the University -

  • PABX is an obsolete technology.  The University’s ability to establish a UC platform is seriously jeopardized unless all the analog-based PABX systems are replaced by digital-based IP Phone systems;
  • Most PABX systems in the University are approaching their end of life, such as the two Fujitsu systems installed in the Kadoorie Biological Science Building and the Faculty of Medicine Building in 1999 and 2001 respectively.  Fujitsu has terminated its PABX product lines for several years; and spare parts for their systems are available only in the second hand market;
  • Some PABX systems of the University are operating at their full capacity with no room for expansion.  The Fujitsu PABX system in the Faculty of Medicine Building, for instance, can no longer accommodate additional phone lines; in other words, new phone lines can only be added by subscribing direct lines from telecom providers; and
  • The individual PABX systems are independent of each other, and they cover different phone number ranges with different prefixes. Internal calls between buildings covered by different systems have to be dialed as external calls.

In view of the above issues, ITS is planning to replace all PABX systems in the University with IP Phone systems progressively. PABX phone lines will be replaced by IP phone lines along with the consequential projects in the Main Campus.  Detailed planning of a separate project to replace the 12 years old, obsolete Fujitsu PABX system in the Faculty of Medicine Building is now underway.  Ultimately, all premises of the University will be covered by IP Phone systems connected seamlessly over the campus network. Ten thousand consecutive phone numbers with prefix “3917” have been reserved for use with IP phones.   We will keep you updated with the development in voice communication in the University.  Please stay tuned.  

I wish you all a prosperous Year of the Snake.


Danny Tang
Director of ITS


[1] IP stands for 'Internet Protocol' and is the 'language' for communication used by most servers and networks, and the Internet.  IP Phone systems operate on IP-based data networks.