EP0147865A2
Expired / Lapsed
EP
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Digital exchange system
Assignee: Fujitsu Ltd
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Filing: 1984-12-28
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Granted: —
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Expires: 2004-12-28
Abstract
Abstract A digital exchange system including exchange terminals, a ditigal network, and a bit rate conversion unit located therebetween. The bit rate conversion unit operates to match low bit-rate channel signals with high bit-rate channel signals acceptable by the digital network, by multiplexing a plurality of the outgoing low bit-rate channel signals. The bit-rate conversion unit operates, on the other hand, to demultiplex the incoming multiplexed low bit-rate channel signals.
Inventors
- 👤 Takashi Hatano
- 👤 Takashi Nara
- 👤 Yutaka Kawato
- 👤 Sumie Okada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 22:27
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q2213/00; H04Q2213/13103; H04Q2213/13106; H04Q2213/13174; H04Q2213/13176; H04Q2213/13202; H04Q2213/13209; H04Q2213/13216; H04Q2213/13292; H04Q2213/13297; H04Q2213/13299
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
238 words
A digital exchange system comprising: a plurality of exchange terminals connected, Via respective transmission lines and network terminations, with corresponding terminal equipment for subscribers; a digital network operative to switch lines between one subscriber and another subscriber and to deal with only a high bit-rate stream of channel signals; and a bit-rate conversion unit, located between said digital network and said exchange terminals, operative to match low bit-rate channel signals with high bit-rate channel signals, transferred with said high bit-rate stream, where both said low bit-rate channel signals and said high bit-rate channel signals are transferred, respectively, in a high bit-rate channel and low bit-rate channel, both channels formed in each of said transmission lines, characterized in that said high bit-rate channel signals, composed of M (M is positive integer) kbit/s signals, are communicated directly to and from said digital network, said low bit-rate channel signals, composed of N (N is positive integer and M > N) kbit/s signals, are communicated to and from said digital network by way of said bit-rate conversion unit, the bit-rate conversion unit is comprised of multiplex means and demultiplex means, said multiplex means is operative to multiplex or less outgoing low bit-rate channel signals to obtain outgoing multiplexed low bit-rate channel signals to be supplied to said digital network, said demultiplex means is operative to demultiplex or less incoming multiplexed low bit-rate channel signals and to distribute them to corresponding exchange terminals.
Claim 2
Dependent Claim
238 words
A digital exchange system comprising: a plurality of exchange terminals connected, Via respective transmission lines and network terminations, with corresponding terminal equipment for subscribers; a digital network operative to switch lines between one subscriber and another subscriber and to deal with only a high bit-rate stream of channel signals; and a bit-rate conversion unit, located between said digital network and said exchange terminals, operative to match low bit-rate channel signals with high bit-rate channel signals, transferred with said high bit-rate stream, where both said low bit-rate channel signals and said high bit-rate channel signals are transferred, respectively, in a high bit-rate channel and low bit-rate channel, both channels formed in each of said transmission lines, characterized in that said high bit-rate channel signals, composed of M (M is positive integer) kbit/s signals, are communicated directly to and from said digital network, said low bit-rate channel signals, composed of N (N is positive integer and M > N) kbit/s signals, are communicated to and from said digital network by way of said bit-rate conversion unit, the bit-rate conversion unit is comprised of multiplex means and demultiplex means, said multiplex means is operative to multiplex or less outgoing low bit-rate channel signals to obtain outgoing multiplexed low bit-rate channel signals to be supplied to said digital network, said demultiplex means is operative to demultiplex or less incoming multiplexed low bit-rate channel signals and to distribute them to corresponding exchange terminals.
Claim 3
Dependent Claim
52 words
A system as set forth in claim 1, wherein said demultiplex means is comprised of a demultiplexer and a distributor connected in series therewith, the demultiplexer receiving the multiplexed incoming low bit-rate channel signals and demultiplexing them, the thus demultiplexed signals being distributed to respective exchange terminals by means of said distributor.
Claim 4
Dependent Claim
52 words
A system as set forth in claim 2, wherein each of said low bit-rate channel signals is composed of at least a control signal to be given to a call processor which controls said digital network to achieve required switching of said lines with respect to the related high bit-rate channel signals.
Claim 5
Dependent Claim
38 words
A system as set forth in claim 3, wherein each of said low bit-rate channel signals is further composed of a data signal to be switched, in said digital network, in accordance with the related said control signal.
Claim 6
Dependent Claim
27 words
A system as set forth in claim 4, wherein each of said control signals is set up with a packet format to form a control signal packet.
Claim 7
Dependent Claim
41 words
A system as set forth in claim 5, wherein each of said data signals is set up with a packet format, the thus set-up data signal packets being communicated, via said digital network, to and from a packet switching digital network.
Claim 8
Dependent Claim
37 words
A system as set forth in claim 6, wherein each of said signal packets constitutes a frame format including therein a data/control discrimination flag which indicates that the signal packet delivers either data information or control information.
Claim 9
Dependent Claim
43 words
A system as set forth in claim 7, wherein each of said incoming signal packets, not yet demultiplexed, constitutes said frame format further including an identification field which indicates to which one of said lines the related signal packet is to be distributed.
Claim 10
Dependent Claim
87 words
A system as set forth in claim 8, wherein each of said frame formats is realized together with other conventional bit areas, i.e., a start flag indicative of the head of the signal packet, an address field indicative of a destination, a control field used for containing therein packet control information, an information field containing therein either data information or control information, a frame check sequence field used for error detection of the signal packet, and an end flag indicative of the end of the signal packet.
Claim 11
Dependent Claim
159 words
A system as set forth in claim 9, wherein said bit rate conversion unit is fabricated as a multiplex/ demultiplex processor comprised of a microprocessor and the following other members supervised thereby, i.e., a read-only memory (ROM) storing therein predetermined control programs to be supplied to the microprocessor, a high-level data link control unit, subject to X.25 protocol of CCITT, being operative to receive said signal packets appearing between said digital network and said exchange terminals, a random-access memory (RAM) momentarily storing therein various sets of information contained in each of said signal packets, a control side input/output interface dealing with multiplexed and demultiplexed control signal packets to be supplied, from the RAM, respectively to said digital network and the corresponding one of said exchange terminals, and a data side input/output interface dealing with multiplexed and demultiplexed data signal packets to be supplied, from the RAM, respectively, to said digital network and the corresponding one of said exchange terminals.
Claim 12
Dependent Claim
36 words
A system as set forth in claim 10, wherein each said terminal equipment for subscribers consists of one or more units selected from, at least, a digital telephone unit, a facsimile unit, and a telex unit.
Claim 13
Dependent Claim
33 words
A system as set forth in claim 11, wherein full-duplex communication is performed, via each said transmission line, between each said network termination and each corresponding said exchange terminal, under an echo-cancellation method.
Claim 14
Dependent Claim
35 words
A system as set forth in claim 11, wherein full-duplex communication is performed, via each said transmission line, between each said network termination and each corresponding said exchange terminal, under a time compression multiplex method.
Claim 15
Dependent Claim
36 words
A system as set forth in claim 11, wherein said digital exchange system is constructed as an integrated service data network (ISDN), in which said integers M and N are selected as 64 and 16, respectively.
References Cited (Backward Citations)
No citation records indexed.
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