Data communication system

• US 4,710,925 A
• Filed: 12/07/1984
• Issued: 12/01/1987
• Est. Priority Date: 12/12/1983
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Negi, Tsuneo
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): Beausoliel, Jr., Robert W.
• Application Number:
  US06/679,558
• Time in Patent Office: 1,089 Days
• Field of Search: 371/5, 371/22, 371/67, 375/34, 375/58, 455/63
• US Class Current: 714/708
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04N 1/33323 transmission mode only, e.g. speed
• CPC Class Codes: H04N 1/33392 Details of handshaking
• CPC Class Codes: H04N 2201/3335 Speed or rate
• CPC Class Codes: H04N 2201/33371 using test signals, e.g. checking error occurrences

Abstract

A test signal is received for testing the transmission rate, the number of errors in the test signal in a predetermined time period is detected, and the number of errors is compared with a predetermined number to determine the proper transmission rate for data communication.

Claims

1. A data communication method comprising the steps of:

receiving a test signal for testing a transmission rate;

dividing a reception period of the test signal into a plurality of periods and detecting an error for each of the periods;

discriminating a failure of the reception of the test signal for each of the periods in accordance with a criterion which is set to become increasely difficult with the lapse of time; and

transmitting a signal representing the failure of the test signal reception to a test signal transmission party, in response to discrimination of the failure of the test signal reception in said discriminating step.

2. A method according to claim 1, wherein, in said detecting step, the number of errors in each of the periods is detected, and in said discriminating step, the number of errors in each of the periods is compared with a predetermined number.

3. A data communication method according to claim 2, wherein said predetermined number varies for each discrimination.

4. A data communication method according to claim 3, wherein said predetermined number decreases with time.

5. A data communication method according to claim 1, wherein said data is image data.

6. A data communication method comprising the steps of:

receiving a test signal for testing a transmission rate;

detecting the number of errors occurring within a second predetermined period of time which commences after termination of a first predetermined period of time measured from a start of the reception of the test signal;

comparing the number of errors with a predetermined number; and

transmitting a signal representing the failure of the reception of the test signal to a party which transmitted the test signal, when the number of errors is larger than the predetermined number in said comparing step.

7. A data communication method according to claim 6, wherein said detecting step comprises detecting the number of errors once during the reception of the test signal.

8. A method according to claim 6, wherein the data includes image data.