Editing System X (telephony) (section)

=== Small exchanges: UXD5 ===
Separately from System X, BT developed the UXD5 ("unit exchange digital"), a small digital exchange which was cost-effective for small and remote communities. Developed by BT at Martlesham Heath and based on the Monarch [[PABX]], the first example was put into service at [[Glenkindie]], Scotland, in 1979, the year before the first System X.<ref>{{Cite web|last=Ames|first=John|date=2015-12-09|title=Memories of the Glenkindie telephone exchange|url=https://blog.nms.ac.uk/2015/12/09/memories-of-the-glenkindie-telephone-exchange/|access-date=2021-05-27|website=National Museums Scotland}}</ref> Several hundred of these exchanges were manufactured by [[Plessey]]<ref>{{Cite web|title=History of Plessey|url=https://www.britishtelephones.com/histples.htm|access-date=2021-05-27|website=www.britishtelephones.com}}</ref> and installed in rural areas, largely in Scotland and Wales. The UXD5 was included as part of the portfolio when System X was marketed to other countries.