|These systems were all maintained by the Post Office/BT before liberalisation. BT/GPO/PO
P.A.B.X.'s were originally only rented but around the early 1980's were offered for sale.
The year 1922 was the first one in which P.A.B.X.'s
introduced. The "Official" P.A.B.X.
has been in use since 1912, but it was in the
nature of an experiment when first installed
and the First World War hindered further
developments of P.A.B.X.'s.
Last revised: October 30, 2022