Data network employing a single transmission bus for overlapping data transmission and acknowledgment signals

• US 4,342,995 A
• Filed: 09/15/1980
• Issued: 08/03/1982
• Est. Priority Date: 09/15/1980
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Burroughs Corp (Unisys Corporation)
• Inventors: Shima, George T.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US06/187,591
• Time in Patent Office: 687 Days
• Field of Search: 340/147 R, 340/147 LP, 340/152 R, 340/163, 340/168 B, 370/85, 370/65, 370/66, 370/60
• US Class Current: 710/107
• CPC Class Codes: G06F 13/4213 with asynchronous protocol
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion

Abstract

This disclosure relates to a network of stations having a single transmission bus. A bus assignment control line is daisy-chained to all of the stations to form a closed loop such that an assignment signal will circulate through the loop and return to the originating station after each station has been given an equal chance to be serviced. Once the bus is assigned to a station, data is transmitted over it and the receiving station returns an acknowledgment signal over a separate acknowledgment line common to all stations. The station that sent the transmission will accept acknowledgment signals only during a finite period of time after its own transmission so as not to be interrupted by other acknowledgment signals at a later time.

Claims

1. A network of stations for data transmissions therebetween, said network comprising:

a single transmission bus;

a plurality of stations coupled to said bus, each station having a bus assignment control pulse receiving and transmitting means;

a bus assignment control line coupled to each of said stations in a serial manner;

each station including a request counter means to count to a given count and, if said each station does not request access to said bus, to signal said pulse receiving and transmitting means to transmit said bus assignment control pulse to said next succeeding station; and

a transmission acknowledgment line coupled to each of said stations;

each of said stations including an acknowledgment means to receive an acknowledgment signal on said acknowledgment line only during a finite period of time after each of said stations has completed transmission on said transmission bus.

2. A network according to claim 1 wherein said acknowledgment means further includes:

an acknowledgment counter to count to a given count to measure said finite period of time.

3. A network according to claim 1 wherein each station further comprises:

a request control line to request access to said transmission bus; and

a request counter means to count to a second given count and, if said each station requests access to said bus, to signal said each station that access has been granted.

4. A network according to claim 3 wherein each station further comprises:

initiate circuit means to initiate an assignment control pulse to be transmitted to said next station after said each station has completed transmission.

5. A network according to claim 4 wherein:

said request counter means resets said initiate circuit means when a particular count is reached which is greater than said second given count.

6. In a network of stations for data transmissions therebetween, said network having a single transmission bus, a station comprising:

a bus assignment control line coupled to said station from a preceding station and to a succeeding station to transmit a bus assignment control pulse;

bus assignment control pulse receiving and transmitting means to receive said bus assignment control pulse;

a request counter means to count to a given count and, if said each station does not request access to said bus, to signal said pulse receiving and transmitting means to transmit said bus assignment control pulse to the next succeeding station;

a transmission acknowledgment line coupled to each of said stations; and

each of said stations including an acknowledgment means to receive an acknowledgment signal on said acknowledgment line only during a finite period of time after said each of said stations has completed transmission on said transmission bus.

7. A station according to claim 6 further including:

a request control line to request access to said transmission bus; and

a request counter means to count to a given count and, if said each station requests access to said bus, to signal said each station that access has been granted.