The PABX is comprised of 21 telephone exchanges which support both analogue and Siemens system phones, such as the Optipoint 500 range. Standard features are supported including pick-up groups, hunt groups, conference calls and call transfer. The system has been in use since 1986, it has been well maintained and upgraded to its current size. However, the system is now coming to the end of its life and mainenance is only guaranteed until 2017. We expect this date to extend but it does mean we are entirely dependent on the second user market for spares.