Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of BE468415ApublicationCriticalpatent/BE468415A/xx
H04M3/42—Systems providing special services or facilities to subscribers
H04M3/58—Arrangements for transferring received calls from one subscriber to another; Arrangements affording interim conversations between either the calling or the called party and a third party
Landscapes
Engineering & Computer Science
(AREA)
Signal Processing
(AREA)
Sub-Exchange Stations And Push- Button Telephones
(AREA)