US3754211A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fast error recovery communication controller
Assignee: International Business Machines Corp
•
Filing: 1971-12-30
•
Granted: 1973-08-21
•
Expires: 1991-12-30
Abstract
Abstract This is a communication controller that is utilized in a network consisting of a plurality of terminal stations, each station capable of transmitting and receiving digital messages. All stations within the system contain a communication controller which detects address or data errors. Properly decoded address and data message information initiates an acknowledgement response from receiving terminal stations. The presence of an address or data error initiates no response from the receiving station. The transmitting station contains automatic means for retransmitting a message if an acknowledgement is not received from the addressed receiver station within a minimum cycle-out period. The communication controller contains automatic means for discarding received messages which are a duplicate of a prior received and properly decoded message.
Inventors
- 👤 E Rocher
- 👤 S Schuster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:18
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/12; H04L1/16; H04L1/18; H04L1/1867; H04L1/188; H04L2001/125
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
222 words
A communications controller for use in a transmitter-receiver terminal connected in a communications network interconnecting at least two terminals, said communications controller comprising: means for formatting digital information into a message frame to be transmitted to a receiving terminal by placing in said message frame, framing information, address information, control information, data information and error detection information; means for receiving message frames and processing those message frames having proper address information; error detection means connected to said means for receiving for detecting errors associated with a received message frame by processing all but the framing information that is present in the received message frame; acknowledgement response means for transmitting an acknowledgement message in response to an indication by said error detection means that an error-free message frame has been received; timing means for determining the expiration of a cycle-out period during which said acknowledgement message is to be received; acknowledgement decode means for properly decoding said acknowledgement message; control means responsive to said acknowledgement decode means, said errpr detection means, and said timing means, for indicating to said terminal to continue transmitting or receiving digital information; automatic retransmission means responsive to said timing means for causing retransmission of the prior sent message frame when an expected acknowledgement message has not been received at said terminal prior to expiration of said cycle-out period.
Claim 2
Dependent Claim
222 words
A communications controller for use in a transmitter-receiver terminal connected in a communications network interconnecting at least two terminals, said communications controller comprising: means for formatting digital information into a message frame to be transmitted to a receiving terminal by placing in said message frame, framing information, address information, control information, data information and error detection information; means for receiving message frames and processing those message frames having proper address information; error detection means connected to said means for receiving for detecting errors associated with a received message frame by processing all but the framing information that is present in the received message frame; acknowledgement response means for transmitting an acknowledgement message in response to an indication by said error detection means that an error-free message frame has been received; timing means for determining the expiration of a cycle-out period during which said acknowledgement message is to be received; acknowledgement decode means for properly decoding said acknowledgement message; control means responsive to said acknowledgement decode means, said errpr detection means, and said timing means, for indicating to said terminal to continue transmitting or receiving digital information; automatic retransmission means responsive to said timing means for causing retransmission of the prior sent message frame when an expected acknowledgement message has not been received at said terminal prior to expiration of said cycle-out period.
Claim 3
Dependent Claim
57 words
The communications controller as defined in claim 1 wherein said timing means comprises: means for generating an access control framing character associated with said message frame; means for decoding said access coNtrol framing character; means for activating said automatic retrans-mission means when said framing character is decoded prior to the receipt of an expected acknowledgement response message.
Claim 4
Dependent Claim
69 words
The communications controller as defined in claim 1 wherein said error detection information as defined in claim 1 generated by means comprising: redundancy check means for processing all digital information contained in said message frame and developing a cyclic redundancy check character; frame synchronization means responsive to said error detection means and said acknowledgement decode means,for providing a state condition indicative of the synchronization state of said communications controller.
Claim 5
Dependent Claim
40 words
The communications controller as defined in claim 2 wherein said error detection means comprises: redundancy check generating means for processing all information other than framing information and generating an error-free message signal; test means for examining said error-free message signal.
Claim 6
Dependent Claim
61 words
The communications controller as defined in claim 3 further comprising: synchronization check means responsive to said error detection means, said framing information, and said means for receiving, for determining if said state condition indicates proper synchronization of the received message frame; switch means responsive to said synchronization check means for controlling the passage of the message frame data to said terminal.
Claim 7
Dependent Claim
50 words
The communications controller as defined in claim 5 further comprising: erase means responsive to said error detection means and said synchronization check means for discarding a received message which has associated therewith either a state condition which indicates a synchronization state error or the absence of an error-free message signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |