We've been informed by our telephony service provider that maintenance will be carried out on one of the network links carrying telephone calls to/from the university PBX to the rest of the world. Maintenance will occur between 23:00 on 24 November 2019 and end at 2:00 on 25 November. During that time, we expect that there will be periods of around a few minutes during which it will not be possible to place or receive external telephone calls. Calls within campus will not be affected.