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EP0047833A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Data communication signalling interface

Assignee: International Business Machines Corp
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Filing: 1981-07-14
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Granted: —
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Expires: 2001-07-14
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Abstract

Abstract The present interface comprises means for exchanging information between a data terminal equipment (DTE) and data circuit terminating equipment (DCE) over a communications line. The specific information to be exchanged is the information indicating the delay period between a request-to-send received at the DCE and a clear-to-send condition occurring some time later in response to the request-to-send. The transmitter signal element timing or clock line (B) is used to convey the information from the DCE to the DTE. In response to receipt at the DCE of a request-to-send signal from the DTE, the DCE temporarily stops the transmission of clock pulses from clock (1), thus preventing the DTE from transmitting data. When the DCE modem has established carrier frequency and has completed its synchronization routine, the DCE re-enables the transmission of clock pulses from clock (1). The clock signals are transmitted at all times except during the request-to-send/clear-to-send delay period.

Inventors

  • 👤 August Philip Arneth
  • 👤 Curtis Leo Foshee

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 23:49
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/14; H04L5/1461; H04L9/00; H04L9/40; H04L69/00; H04L69/30; H04L69/32; H04L69/322; H04L69/323

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 201 words
Data communications signalling interface between a local communication equipment (DCE) and a remote station (DTE) which does not include a separate control line for granting to a remote requesting station a clear-to-send authorization control signal, characterized in that said local communication equipment (DCE) comprises: a transmission timing generator means (5), a clocking pulse generator (I) for transmitting clock pulses to a transmission clock line (B), means (C) for receiving a request-to-send signal from the remote station (DTE), first logic means (4) responsive to the request-to-send signal for initiating the generation of carrier frequency and establishing carrier synchronization between the points to be connected for communication, said first logic means including means for indicating the completion of establishing the carrier frequency and synchronization, and second logic means (2) interposed between said clocking pulse generator (1) and said transmission clock line (B) at said interface, said second logic means being responsive to the receipt of a request-to-send signal to temporarily block the passage of said clock pulses and responsive to an indication from said first logic means (4) that carrier and synchronization have been established, for unblocking said clocking information to said clock line (B) thereby permitting said remote equipment to begin transmission.
Claim 2
Dependent Claim 201 words
Data communications signalling interface between a local communication equipment (DCE) and a remote station (DTE) which does not include a separate control line for granting to a remote requesting station a clear-to-send authorization control signal, characterized in that said local communication equipment (DCE) comprises: a transmission timing generator means (5), a clocking pulse generator (I) for transmitting clock pulses to a transmission clock line (B), means (C) for receiving a request-to-send signal from the remote station (DTE), first logic means (4) responsive to the request-to-send signal for initiating the generation of carrier frequency and establishing carrier synchronization between the points to be connected for communication, said first logic means including means for indicating the completion of establishing the carrier frequency and synchronization, and second logic means (2) interposed between said clocking pulse generator (1) and said transmission clock line (B) at said interface, said second logic means being responsive to the receipt of a request-to-send signal to temporarily block the passage of said clock pulses and responsive to an indication from said first logic means (4) that carrier and synchronization have been established, for unblocking said clocking information to said clock line (B) thereby permitting said remote equipment to begin transmission.
Claim 3
Dependent Claim 44 words
Signalling interface according to claim 1, characterized in that said first logic means (4) include an AND gate the inputs of which are responsive to the signals in said request-to-send signal receiving means (C) and in said carrier frequency and synchronization completion indicating means.
Claim 4
Dependent Claim 42 words
signalling interface according to claim 1 or 2, characterized in that said second logic means (2) include an AND gate the inputs of which are responsive to the signals in said timing generator means (5) and in said clocking pulse generator (1).

References Cited (Backward Citations)

US4009336A Cited

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