Communication control apparatus

• US 5,384,778 A
• Filed: 10/01/1993
• Issued: 01/24/1995
• Est. Priority Date: 10/20/1992
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Okamoto, Yasushi, Arimoto, Akiya
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US08/130,254
• Time in Patent Office: 480 Days
• Field of Search: 370/85.1, 370/85.2, 370/85.3, 370/85.6, 340/825.5, 340/825.51, 340/825.52, 371/20.1, 371/68.2, 371/, 371/33
• US Class Current: 370/421
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/40013 Details regarding a bus controller
• CPC Class Codes: H04L 12/40032 Details regarding a bus interface enhancer
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Abstract

A communication control apparatus is constituted such that, when functioning as a receiving side, an IFR 20 is replied only when receiving normally or only when not receiving normally, also at the time of multiple address communication, when functioning as the receiving side, the IFR 20 is replied only when receiving normally or only when not receiving normally, and furthermore, at the time of multiple address communication, a reply data row is replied only when an IFR control code 57 sent from a transmitting side is larger than respective source addresses, or only when smaller. It is possible to find out occurrence of errors in a unit on the transmitting side, by one frame communication, and accuracy of the multiple address communication is improved, besides the source address of the unit having an unspecific source address can be retrieved easily in one specific unit.

Claims

1. A communication control apparatus, which is included respectively in a plurality of communication terminals connected to a common data line so as to transmit data from one terminal functioning in a transmitting mode to any other terminal functioning in a receiving mode, and which transmits and receives communication data by a set of data bytes constituting a packet frame on said common data line, including a series of transmitting data bytes sent to said common data line from the communication terminal functioning in the transmitting mode, and which transmits a reply data byte on said common data line from a communication terminal functioning in a receiving mode acknowledging the transmitting data bytes in a reply section, and which, when functioning in a receiving mode, detects collisions of the reply data byte sent to said common data line by itself on the common data line in the reply section, and stops sending out the reply data byte when collision is detected, comprising:

means for sending said reply data byte only when a packet frame is received normally on said common data line when in a transmitting mode or only when not received normally, when functioning in a receiving mode;

means for storing the reply data byte sent from terminals in the receiving mode, when functioning in a transmitting mode; and

means for detecting whether or not the reply data byte has been sent, when functioning in the transmitting mode.

2. A communication control apparatus, which is included respectively in a plurality of communication terminals connected to a common data line for multiple address communication, which transmits data of the same contents from one terminal functioning in a transmitting mode to a plurality of terminals functioning in a receiving mode, and which transmits and receives communication data by a set of data bytes constituting a packet frame on the common data line including a series of transmitting data bytes sent to said common data line from the communication terminal functioning in a transmitting mode, and which transmits a reply data byte on said common data line from a communication terminal functioning in a receiving mode acknowledging the transmitting data bytes in a reply section, and which when functioning in a receiving mode, detects collisions of the reply data byte sent to said common data line by itself on said common data line in the reply section, and stops sending out a reply data byte when collision is detected, comprising:

means for sending the reply data byte, only when receiving normally the series of transmitting data bytes sent to said common data line from a terminal in said transmitting mode or only when not receiving normally, when functioning in the receiving mode;

means for storing the reply data byte sent from a terminal in the receiving mode when functioning in the transmitting mode; and

means for detecting whether or not the reply data byte has been sent, when functioning in the transmitting mode.

3. A communication control apparatus, which is included respectively in a plurality of communication terminals connected to a common data line for multiple address communication, which transmits data of the same contents from the one functioning as a transmitting side to the other plurality functioning as receiving sides, and respectively allocated with inherent data for respective identification, transmits and receives communication data by a set of data rows constituted on said common data line, by a series of transmitting data rows sent to said common data line from the communication terminal functioning as the transmitting side in a transmitting section, and a reply data row sent to said common data line from the communication terminal functioning as the receiving side against the transmitting data rows in a reply section, and when functioning as the receiving side, detects collisions of the reply data row sent to said common data line by itself on said common data line in the reply section, and stops to send out the reply data row when the collision is detected, comprising:

means for replying inherent data as the reply data row, only when said respectively allocated inherent data is smaller than a predetermined code included in the receiving data row received from said common data line, whet, functioning as the receiving side;

means for storing the reply data row replied from the receiving side, when functioning as the transmitting side; and

means for detecting whether or not the reply data row has been replied, when functioning as the transmitting side.

4. A communication control apparatus, which is included respectively in a plurality of communication terminals connected to a common data line for multiple address communication, which transmits data with the same contents from one terminal functioning in a transmitting mode to the other plurality of terminals functioning in a receiving mode, the terminals being respectively allocated with inherent data for respective identification, which transmits and receives communication data by a set of data bytes constituting a packet frame on the common data line, by a series of transmitting data bytes sent to said common data line from a communication terminal functioning in the transmitting mode, and a reply data byte sent to said common data line from communication terminals functioning in the receiving mode acknowledging the transmitting data bytes in a reply section, and which when functioning in the receiving mode, detects collisions of the reply data byte sent to said common data line by itself on said common data line in the reply section, and stops sending out the data byte when collision is detected, comprising:

means for sending inherent data as the reply data byte, only when said respectively allocated inherent data is larger than a predetermined code included in the receiving data byte received from said common data line, when functioning in the receiving mode;

means for storing the reply data byte sent from terminals in the receiving mode, when functioning in the transmitting mode; and

means for detecting whether or not the reply data byte has been sent, when functioning in the transmitting mode.

5. A communication control apparatus, which is included respectively in a plurality of communication terminals connected to a common data line for multiple address communication, which transmits data of the same contents from one terminal functioning in a transmitting mode to the other terminals functioning in receiving modes, and respectively allocated with inherent data for respective identification, which terminal transmits and receives communication data by a set of data bytes constituting a packet frame on the common data line by a series of transmitting data bytes sent to said common data line from the communication terminal functioning in a transmitting mode, and reply data byte sent to said common data line from a communication terminal functioning in the receiving mode acknowledging the transmitting data bytes in a reply section, and which when functioning in a receiving mode detects collisions of the reply data byte sent to said common data line by itself on said common data line in the reply section, and stops sending out the reply data byte when collision is detected, comprising:

reply data byte sending means for sending inherent data as the reply data byte, only when said respectively allocated inherent data is larger or smaller than a predetermined code included in the receiving data byte received from said common data line, when functioning in the receiving mode;

judging means for judging whether to send inherent data by the reply data byte sending means as the reply data byte, according to predetermined data included in receiving data bytes received from said common data line only when said inherent data is larger than said predetermined code, or to send said inherent data as the reply data byte, only when said inherent data is smaller than said predetermined code, when functioning in the receiving mode;

means for storing the reply data byte sent from the receiving side, when functioning in the transmitting mode; and

means for detecting whether or not the reply data byte has been sent, when functioning in the transmitting mode.