Digital serial communications hub

• US 6,940,868 B1
• Filed: 04/20/1999
• Issued: 09/06/2005
• Est. Priority Date: 04/20/1999
• Status: Active Grant

• Current Assignee: ABB Incorporated (ABB Limited)
• Original Assignee: ABB Incorporated (ABB Limited)
• Inventors: Laplace, Carl J. Jr., Barbour, Erskine R.
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): ABELSON, RONALD B
• Application Number:
  US09/295,163
• Time in Patent Office: 2,331 Days
• Field of Search: 370465-470, 370/252, 370401-402, 370/294, 370/521, 370/463, 370/279, 370/293, 370/315, 359/113, 359/118, 359/128, 359/110, 709/232, 709/401, 714/774, 714/776, 375/222
• US Class Current: 370/466
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 3/542 the information being in digital form
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]

Abstract

A digital serial communications hub has the ability to delay, route and regenerate data on the fly at mixed baud rates, mixed character framing bits, and mixed protocols without prior setup. In addition, the communications hub stores and retrieves serial data in the time domain, and employs a simple and reliable error correction routine that takes advantage of the time domain format of the data. Physically, the communications hub is implemented as a circuit card integrating a central processor with several serial communications ports. The serial ports connect to a combination of electrical interfaces that include RS232, RS485, TTL, and Fiber Optic. The serial communication ports are routed through a central flow processor that controls data flow into and out of the circuit card via serial communications connectors.

Claims

1. A digital serial communications hub comprising:

(a) a controller; and

,

(b) a plurality of receiver-transmitter units operatively coupled to the controller;

wherein the controller is programmed to delay, route and regenerate data at mixed baud rates, mixed character framing bits and mixed protocols by, in part, digitizing and quantizing all received data in a time domains, independent of a protocol necessary for understanding said received data.

2. A digital serial communications hub as recited in claim 1, wherein the controller is further programmed to filter for error correction and store in memory the received data.

3. A digital serial communications hub as recited in claim 2, wherein the controller is further programmed to perform the following steps:

(i) measuring the received data'"'"'s transition times values in the time domain, and storing in memory the transition time values;

(ii) analyzing the transition time values to determine if any error correction should be applied to the transition time values, and if so, applying an error correction procedure to the transition time values in need of error correction; and

(iii) reconstructing the received data with error correction.

4. A digital serial communications hub as recited in claim 3, wherein the correction procedure of step (ii) further comprises:

(a) determining a common denominator of a standard baud rate, wherein the common denominator is a unit of time equal to a time employed to transmit a single bit at a certain baud rate;

(b) dividing each transition time value of the received data by the common denominator; and

,

(c) rounding off each transition time value to a closest interval equal to an integral number of common denominator periods.

5. A digital serial communications hub as recited in claim 3, wherein the controller is a microcontroller including a time module, and the step of reconstructing the received data is performed by sequentially moving the transition time values into a timer module wherein the transition time values are used to reconstruct the received data, including the use of a port identifier associated with the received data to determine a port or ports on which the received data will be re-transmitted.

6. A digital serial communications hub as recited in claim 1, wherein the controller is further programmed to delay retransmission of the received data.

7. A method for operating a digital serial communications hub, comprising

(i) digitizing and quantizing all received data in a time domain said received data further comprising mixed baud rates, mixed character framing bits, and mixed protocols;

(ii) error correcting the received data in the time domain;

(iii) retransmitting the error corrected received data, mixed baud rates, mixed character framing bits and mixed protocols, independent of a protocol necessary for understanding said received data.

8. A method as recited in claim 7, further comprising the following steps:

(i) measuring the received data'"'"'s transition times in the time domain; and

,

(ii) storing in memory the data transition time values;

(iii) analyzing the measured time values to determine if any error correction should be applied to the data transition time values and, if so applying an error correction procedure to the data transition time values in need of error correction; and

(iv) reconstructing the received data with error correction.

9. A method as recited in claim 8, wherein the error correction procedure of step (iii) further comprises:

(a) determining a common denominator of a standard baud rate, wherein the common denominator is a unit of time equal to a time employed to transmit a single bit at a certain baud rate;

(b) dividing each data transition time value of the received data by the common denominator; and

rounding off each data transition time value to a closest interval equal to an integral number of common denominator periods.

10. A digital serial communications hub comprising:

(a) a controller; and

,

(b) a plurality of receiver-transmitter units operatively coupled to the controller;

wherein the controller is programmed to delay, route and regenerate data at mixed baud rates, mixed character framing bits and mixed protocols by, in part, digitizing and quantizing all received data in a time domain without knowledge of protocol, framing or other information necessary to digitizing or quantifying said received data.

11. A digital serial communications hub as recited in claim 10, wherein the controller is further programmed to filter for error correction and store in memory the received data.

12. A digital serial communications hub as recited in claim 11, wherein the controller is further programmed to perform the following steps:

(i) measuring the received data'"'"'s transition time values in the time domain, and storing in memory the transition time values;

(ii) analyzing the stored transition time values to determine if any error correction should be applied to the transition time values, and if so, applying an error correction procedure to the transition time values in need of error correction; and

,

(iii) reconstructing the received data with error correction.

13. A digital serial communications hub as recited in claim 12, wherein the correction procedure of step (ii) further comprises:

(a) determining a common denominator of a standard baud rate, wherein the common denominator is a unit of time equal to a time employed to transmit a single bit at a certain baud rate;

(b) dividing each time value of the received data by the common denominator; and

,

(c) rounding off each time value to a closest interval equal to an integral number of common denominator periods.

14. A digital serial communications hub as recited in claim 12, wherein the controller is a microcontroller including a time module, and the step of reconstructing the received data is performed by sequentially moving the transition time values into a timer module wherein the transition time values are used to reconstruct the received data, said reconstruction step further comprising the use of a port identifier associated with the received data to determine a port or ports on which the received data will be retransmitted.

15. A digital serial communications hub as recited in claim 10, wherein the controller is further programmed to delay retransmission of the received data.

16. A method for operating a digital serial communications hub, comprising:

(i) digitizing and quantizing all received data in a time domain said data further comprising mixed baud rates, mixed character framing bits, and mixed protocols;

(ii) error correcting the received data in the time domain;

(iii) retransmitting the error corrected received data, mixed baud rates, mixed character framing bits and mixed protocols, without knowledge of protocol, framing or other information necessary to digitizing or quantifying said received data.

17. A method as recited in claim 16, further comprising the following steps:

(i) measuring the received data'"'"'s transition time values in the time domain;

(ii) storing in memory the transition time values;

(iii) analyzing the transition time values to determine if any error correction should be applied to the transition time values and, if so;

applying an error correction procedure to the transition time values in need of error correction; and

(iv) reconstructing the received data with error correction.

18. A method as recited in claim 17, wherein the error correction procedure of step (iii) further comprises:

(a) determining a common denominator of a standard baud rate, wherein the common denominator is a unit of time equal to a time employed to transmit a single bit at a certain baud rate;

(b) dividing each time value of the received data by the common denominator; and

,

(c) rounding off each time value to a closest interval equal to an integral number of common denominator periods.