EP0028104A1
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EP
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Signal control system for a time-division speech network
Assignee: Fujitsu Ltd
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Filing: 1980-10-16
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Granted: —
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Expires: 2000-10-16
Abstract
Abstract A digital pad switch DSP is inserted in a highway JHW 1 , JHW 2 of the time-division speech network. For an input signal, from incoming highway JHW 1 , the digital pad switch DSP is operable to send out, on outgoing highway JHW 2 , any selected one of the following: a signal the same as the input signal, signals corresponding to the input signal as attenuated by predetermined amounts, and a zero level signal. The digital pad switch has read only memories ROM o , ROM 3 , ROM 5 , ROM 6 and ROM ∞ . Each ROM has an address corresponding to each possible input signal. In response to the input signal ROM o sends out an identical signal, ROM 3 , ROM 5 and ROM 6 send out respective signals corresponding to the input signal as attenuated by 3 dB. 5 dB and 6 dB respectively. ROM ∞ sends out a zero level signal. Under control of pad switch control memory PSM the selector SEL sends out only the signal from the appropriate ROM to highway JHW 2 .
Inventors
- 👤 Hiroshi Ishikawa
- 👤 Takuhito Kojima
- 👤 Eiji Minamitani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 08:54
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
66 words
A signal control system for a time-division speech network, characterised in that a digital pad switch is provided along a highway of the speech network, the digital pad switch being selectively operable in respect of an input signal received thereat to send out a signal corresponding to the input signal as received or a signal corresponding to the input signal as attenuated by a predetermined amount.
Claim 2
Dependent Claim
66 words
A signal control system for a time-division speech network, characterised in that a digital pad switch is provided along a highway of the speech network, the digital pad switch being selectively operable in respect of an input signal received thereat to send out a signal corresponding to the input signal as received or a signal corresponding to the input signal as attenuated by a predetermined amount.
Claim 3
Dependent Claim
48 words
A speech control system as claimed in claim 1, wherein the digital pad switch is selectively operable in respect of an input signal received thereat to send out a signal corresponding to the input signal as received or a zero level signal (i.e. the input signal infinitely attenuated).
Claim 4
Dependent Claim
218 words
A signal control system as claimed in claim 1 or 2, wherein a digital pad switch is inserted in each highway of a time-division speech network in which there are disposed time switches on the backward side of the speech network, each time switch reading out speech information from a speech memory in the order of addresses assigned by the output from a channel counter; each digital pad switch being arranged and operable so as to send out on a speech path passing through the digital pad switch, under control of a common control unit, a selected signal which is one of the following:- a signal the same as an input signal from the speech path to the digital pad switch, signals respectively corresponding to the input signal as attenuated by predetermined amounts and a zero level signal, unaffected by the magnitude of the input signal; in a case in which the speech path set up in the time-division speech network is to be cut-off, the digital pad switch being controlled so as to send out the zero level signal as a signal on the speech path passing through the digital pad switch, and the zero level signal being written in a speech memory of a time switch on the backward side, thereafter cutting off the speech path.
Claim 5
Dependent Claim
220 words
A signal control system as claimed in claim 1 or 2, wherein a digital pad switch is inserted in each highway of a time-division speech network in which there are disposed time switches on the backward side of the speech network, each time switch reading out speech information from a speech memory in the order of addresses assigned by the output from a channel counter; each digital pad switch being arranged and operable so as to send out on a speech path passing through the digital pad switch, under control of a common control unit, a selected signal which is one of the following:- a signal the same as an input signal from the path to the digital pad switch, signals respectively corresponding to the input signal as attenuated by predetermined amounts and a zero level signal corresponding to an infinitely great attenuation of the input signal regardless of its magnitude; the digital pad switch being so controlled by the common control unit as to repeatedly send out the zero level signal for a desired period of time in response to a signal sent out from a continuous tone signal generator connected to the input end of the time-division speech network and reaching the output end thereof via a speech path thereof, thereby turning ON and OFF the tone signal.
Claim 6
Dependent Claim
173 words
A signal control system as claimed in claim 1, wherein a digital pad switch is inserted in each highway of a time-division speech network in which there are disposed time switches on the backward side of the speech network, each time switch reading out speech information from a speech memory in the order of addresses assigned by the output from a channel counter; the digital pad switch being arranged and operable so as to send out, under the control of a common control unit, a selected signal which is one of the following:- a signal of the same level as an input signal from each channel to the digital pad switch, and signals respectively corresponding to the input signal as attenuated by predetermined amounts; the digital pad switch being so controlled that a signal sent out from a tone signal generator connected to the input end of the time-division speech network and reaching the output end thereof via a speech path thereof is attenuated by the digital pad switch in a stairstep manner.
Claim 7
Dependent Claim
71 words
A signal control system as claimed in claim 5, wherein a howler tone generator of a constant level isconnected as the tone signal generator to the input end of the time-division speech network; and insertion loss of a signal sent out from the howler tone generator via a speech channel of the time-division speech network to the output end thereof is decreased in a stairstep manner in accordance with preset timings.
Claim 8
Dependent Claim
105 words
A signal control system as claimed in claim 5, wherein a multi-frequency signal transmitter for sending out a multi-frequency signal of a constant level is connected to the input end of the time-division speech network; a multi-frequency signal receiver is connected to the output end of the time-division speech network; the multi-frequency signal transmitter is connected to the multi-frequency receiver via a speech channel of the time-division speech network; and the multi-frequency signal passing through the speech channel is attenuated in a stairstep manner by controlling the digital pad switch, thereby to control a signal for testing the receiving sensitivity of the multi-frequency signal receiver.
References Cited (Backward Citations)
GB1444919A
Cited
FR2226797A1
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US3985966A
Cited
FR2367399A1
Cited
US4152548A
Cited
WO1980000289A1
Cited
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