Assertion: carrier's system | /r/HasProperty | replaced with european standard ones
Facets:
value: merely
type: DEGREE
value: in the 1980s
type: TEMPORAL
Source sentences:
text: Similar British 23 channel systems at 1.536 megabaud in the 1970s were equipped with ternary signal repeaters, in anticipation of using a 3B2T or 4B3T code to increase the number of voice channels in future, but in the 1980s the systems were merely replaced with European standard ones.