EP0316536A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Terminal unit in information transmission system
Assignee: OFFERTA DI LICENZA AL PUBBLICO
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Filing: 1988-09-16
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Granted: —
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Expires: 2008-09-16
Abstract
Abstract A terminal unit (3) for use in an information transmission system disposed between an information transmission line (1) in the information transmission system constituted of signal lines for transmitting a signal by conduction therethrough of a direct current having positive polarity and negative polarity and controlled equipment as one terminal of the system, including at least a coupling circuit (5) for transmitting and receiving a signal to and from the transmission line by converting the signal into a direct current as aforesaid and converting such a direct current into the signal, a transmission control circuit (12) controlling transmission and reception of a signal according to a protocol for signal transmission, and a transmission circuit (8) and a reception circuit (11) disposed between the coupling circuit and transmission control circuit for making signal transmission and reception, respectively, and further, comprising a polarity detection circuit for detecting polarity of the direct current voltage supplied from the signal lines and a polarity switching circuit for switching polarities of a signal delivered to the transmission line depending upon the result of detection in the polarity detection circuit.
Inventors
- 👤 Yoshiji Mitsubishi Denki Kabushiki K. Minagawa
- 👤 Yoshiyuki Mitsubishi Denki Kabushiki K. Honda
- 👤 Yoshiaki Mitsubishi Denki Kabushiki K. Ito
- 👤 Toshiyasu Mitsubishi Denki Kabushiki K. Higuma
- 👤 Mitsunobu Mitsubishi Denki Kabushiki K. Esaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 18:12
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/2803; H04L12/2838; H04B; H04B3/00; H04B3/54; H04B3/548; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4917; H04L25/4923; H04L25/4925; H04B2203/00; H04B2203/54; H04B2203/5404; H04B2203/5408; H04B2203/5416; H04B2203/5429; H04B2203/5458; H04B2203/5462; H04B2203/547; H04B2203/5483; H04L2012/284; H04L2012/2843; H04L2012/2847; H04L2012/285
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
190 words
In a terminal unit for use in an information transmission system disposed between an information transmission line in the information transmission system constituted of signal lines for transmitting a signal by conduction therethrough of a direct current having positive polarity and negative polarity and controlled equipment as one terminal of the system and including at least a coupling circuit for transmitting and receiving a signal to and from the transmission line by converting the signal into a direct current as aforesaid and converting such a direct current into the signal, a transmission control circuit controlling transmission and reception of a signal according to a protocol for signal transmission, and a transmission circuit and a reception circuit disposed between said coupling circuit and transmission control circuit for maiing signal transmission and reception, respectively, said terminal unit for use in an information transmission system comprising: a polarity detection circuit for detecting the polarity of the direct current voltage supplied to each of said signal lines; and a polarity switching circuit for switching polarities of the signal delivered to said transmission line depending upon the result of detection in said polarity detection circuit.
Claim 2
Dependent Claim
190 words
In a terminal unit for use in an information transmission system disposed between an information transmission line in the information transmission system constituted of signal lines for transmitting a signal by conduction therethrough of a direct current having positive polarity and negative polarity and controlled equipment as one terminal of the system and including at least a coupling circuit for transmitting and receiving a signal to and from the transmission line by converting the signal into a direct current as aforesaid and converting such a direct current into the signal, a transmission control circuit controlling transmission and reception of a signal according to a protocol for signal transmission, and a transmission circuit and a reception circuit disposed between said coupling circuit and transmission control circuit for maiing signal transmission and reception, respectively, said terminal unit for use in an information transmission system comprising: a polarity detection circuit for detecting the polarity of the direct current voltage supplied to each of said signal lines; and a polarity switching circuit for switching polarities of the signal delivered to said transmission line depending upon the result of detection in said polarity detection circuit.
Claim 3
Dependent Claim
74 words
A terminal unit according to claim 1 further comprising a power receiving circuit disposed between said coupling circuit and said polarity detection circuit including at least an inductance serving as a high impedance to a transmitted signal and a stabilizer circuit for voltage stabilization, said power receiving circuit being provided with a full-wave rectifier circuit connected in series with said inductance and the output thereof being connected with the input of said stabilizer circuit.
Claim 4
Dependent Claim
136 words
A terminal unit according to claim 2, wherein said polarity detection circuit is constituted of a resistor connected in parallel with said inductance of said powe5 receiving circuit and a photocoupler, of which anode side is connected with said resistor and cathode side is connected with the input side of said full-wave rectifier circuit, and which includes a light emitting diode and a phototransistor, and said polarity switching circuit is constituted of a switching transistor, of which emitter is connected with the emitter of said photocoupler and base is connected with the collector of said photocoupler, and a relay connected between the collector of said transistor and the junction point of said photocoupler and the base of said transistor with its contacts disposed between outputs of said transmission control circuit and inputs of said transmission circuit.
Claim 5
Dependent Claim
135 words
A terminal unit according to claim 3, wherein said contacts of said relay consist of a first contact, which has a normally open contact, a normally closed contact, and a common contact to be connected with either of said contacts depending upon a switching output, and a second contact, which has a normally open contact connected in juxtaposition with the normally closed contact of said first contact, a normally closed contact connected with the normally open contact of said first contact, and a common contact, and outputs from two output terminals of said transmission control circuit to said transmission circuit are switched by changing over of said contacts depending upon the result of detection in said polarity detection circuit, whereby the polarities of a signal transmitted to the transmission line are adapted to be switched.
Claim 6
Dependent Claim
146 words
A terminal unit according to claim 2, wherein said polarity detection circuit is constituted of a resistor connected in parallel with said inductance of said power receiving circuit and a photocoupler, of which anode side is connected with said resistor and cathode side is connected with the input side of said full-wave rectifier circuit, and which includes a light emitting diode and a phototransistor, and said polarity switching circuit is constituted of a control terminal for polarity detection disposed on said transmission control circuit for receiving a detection output of said photocoupler and a logical operator disposed within said transmission control circuit and provided with a polarity switching program including at least a routine for identifying whether the level of the detection output is high or low and a routine for reversing the transmission polarity depending upon the result of identification executed in said identifying routine.
Claim 7
Dependent Claim
67 words
A terminal unit according to claim 1, wherein it is adapted such that said polarity detection circuit detects the polarity of a start bit which has come in at first after the power source was turned on and the polarity switching circuit switches the polarities of an encoded baseband signal to be delivered to said information transmission line depending upon the output of said polarity detection circuit.
Claim 8
Dependent Claim
133 words
A terminal unit according to claim 6, wherein said polarity detection circuit is constituted of two polarity identification terminals provided on said transmission control circuit for receiving outputs of two comparators provided in said reception circuit and a logical operator for identifying the polarity of a signal over the transmission line depending upon the two inputs at said polarity determination terminals, and said polarity switching circuit is constituted of a switching terminal provided on said transnission control circuit for delivering a switching signal depending upon the output of said logical operator, a switching transistor whose base side is connected with said switching terminal, and a relay connected with the collector of said switching transistor with its contacts disposed between output terminals of said transmission control circuit and input terminals of said transmission circuit.
Claim 9
Dependent Claim
43 words
A terminal unit according to claim 7, wherein said polarity detection circuit is constituted of a microcomputer having a routine for determining the polarity of a signal and also having a routine for controlling outputs delivered to said switching terminal and output terminals.
Claim 10
Dependent Claim
26 words
A terminal unit according to claim 6, wherein said baseband signal delivered to said information transmission line is coded in the alternate mark inversion (AMI) mode.
Claim 11
Dependent Claim
30 words
A terminal unit according to claim 9, wherein said polarity detection circuit is adapted to transmit a start bit identification signal for identifying said start bit to said transmission line.
Claim 12
Dependent Claim
75 words
A terminal unit according to claim 1, wherein said polarity detection circuit is adapted to detect the signal polarity of said transmission line depending upon an output of a polarity setting device outputting the signal for indicating the polarity to said transmission line, and said polarity switching circuit is adapted to switch the polarity of an encoded baseband signal to the polarity having a predetermined relation with the polarity indicated by said polarity setting device.
Claim 13
Dependent Claim
63 words
A terminal unit according to claim 11, wherein said polarity detection circuit includes a current limiting resistor for preventing inflow of a large direct current, a photocoupler for polarity detection provided with a light emitting diode, pull-up resistors disposed on the output side of said photocoupler, and polarity detection input terminals provided on said transmission control circuit for receiving outputs of said photocouplers.
Claim 14
Dependent Claim
112 words
A terminal unit according to claim 11, wherein said polarity switching circuit is connected at its input side with output terminals of said transmission control circuit and connected at its output side with said transmission circuit and is constituted of a pair of NOT circuits each thereof receiving the polarity setting output, a pair of first NAND circuits receiving output of said NOT circuit and output from one of the output terminals, a pair of second NAND circuits receiving the polarity setting output and output from the other one of the output terminals, and a pair of NAND circuit each thereof receiving output of each of said first and second NAND circuits.
Claim 15
Dependent Claim
97 words
A terminal unit according to cliam 11, wherein said polarity setting device is constituted of a D.C. power source for supplying a direct current to said transmission line, a current limiting resistor connected to the positive electrode side of said D.C. power source, a current detector connected at both ends of said resistor in parallel therewith for detecting the quantity of a direct current, and a pair of switches disposed between said resistor and the positive signal line and between the negative electrode of said power source and the negative signal line for cutting off the current.
Claim 16
Dependent Claim
97 words
A terminal unit according to cliam 11, wherein said polarity setting device is constituted of a D.C. power source for supplying a direct current to said transmission line, a current limiting resistor connected to the positive electrode side of said D.C. power source, a current detector connected at both ends of said resistor in parallel therewith for detecting the quantity of a direct current, and a pair of switches disposed between said resistor and the positive signal line and between the negative electrode of said power source and the negative signal line for cutting off the current.
Claim 17
Dependent Claim
82 words
A terminal unit according to claim 11, wherein a switching transistor and a relay are disposed between a coupling transformer provided on the output side of said polarity switching circuit and said transmission line, said transistor having its base side connected with a polarity detection signal output terminal provided on said transmission control circuit and its emitter side grounded, and said relay being connected with the collector side of said transistor and having its contacts between said transformer and said transmission line.
References Cited (Backward Citations)
No citation records indexed.
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