Patent
1977-06-13
1978-10-10
Cooper, William C.
179 15AP, H04M 356
Patent
active
041198077
ABSTRACT:
A pulse code modulation (PCM) time division multiplex (TDM) telephone exchange to which n telephone lines are sequentially connected during n respective sequential time slots. An unlimited number of phones may be connected together for conference purposes by means of a summation memory in which each conference storage location is used for accumulating the sum of message samples from one or more lines during a write-in cycle and supplying the sum of the message samples to one or more of the lines during a subsequent read-out cycle. The summation memory is indirectly addressed by a connection control memory. A portion of each message sample stored in a sample memory is subtracted from each sum of message samples read out during the same time slot from the summation memory, so that a speaker hears an attenuated sidetone version of his own voice.
REFERENCES:
patent: 3903372 (1975-09-01), Aro
patent: 4007338 (1977-02-01), McLaughlin
Christoffersen M.
Cohen Samuel
Cooper William C.
Olson Carl V.
RCA Corporation
LandOfFree
Digital time division multiplex switching system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital time division multiplex switching system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital time division multiplex switching system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1767784