Expandable communication system with automatic data concentrator detection

• US 5,222,062 A
• Filed: 10/03/1991
• Issued: 06/22/1993
• Est. Priority Date: 10/03/1991
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: VanBuskirk, Michael R., Sharma, Sudhir K., Kunz, Richard A., Meinecke, Jon M., Salzman, Clyde Jr., Noble, Robert L. III
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Blum, Russell W.
• Application Number:
  US07/771,121
• Time in Patent Office: 628 Days
• Field of Search: 370/94.1, 370/56, 370/112, 370/84, 370/58.2, 370/58.3, 370/68.1
• US Class Current: 370/218
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal

Abstract

A communication system including one or more host adapters connected to a host computer, each adapter having multiple serial communication ports for transferring data between the computer and several TTY devices. Several of the adapter'"'"'s serial ports include a high speed serial link for communicating with a data concentrator. The adapter automatically detects the presence of a concentrator connected to a switchable port and switches to the high speed link. Each concentrator includes multiple serial ports for communicating with TTY devices, and a high speed serial link for communicating with the adapter'"'"'s high speed link. The concentrators allow more than one TTY device to share a single adapter serial port. Data from all of the TTY devices is accumulated into an adapter data buffer during a configurable time period or until a certain amount of data is accumulated, at which time the adapter interrupts the computer and transfers the accumulated data to the computer in one transfer operation. Likewise, the computer accumulates data for the TTY devices and transfers this data to the adapter in one transfer operation. Communication between the adapters and concentrators through the high speed serial communication link is implemented using a small fixed-size addressed packet to achieve a low overhead, high performance communications protocol. Each high speed link between an adapter and a concentrator is implemented to provide inherent flow control of data. The concentrators include a fail safe global flow control mechanism to prevent overflow of data from the TTY devices.

Claims

1. A data concentrator detection system, comprising:

a data concentrator, including;

communication means for transmitting a data packet and an indication signal indicative of said data concentrator being powered-up and ready to transmit said data packet, and for receiving a ready signal indicative of when an external device is connected to said communication means and ready to receive said data packet, wherein if said ready signal is detected, said communication means transmits said data packet; and

a host adapter, including;

communication means for receiving said indication signal and said data packet from said data concentrator, and for transmitting said ready signal to said data concentrator after said communication means is ready to receive said data packet,

a connector for coupling said host adapter communication means to an external transmitting device,

a switch connected to said communication means and said connector wherein if said switch is enabled, said switch couples said communication means to said connector, and if said switch is disabled, said switch de-couples said communication means from said connector, and

means connected to said communication means and said switch means for detecting said data concentrator, said detection means including;

means for comparing data received from an external device with a predetermined set of valid data packets, wherein said detection means periodically enables said switch, and if said indication signal is detected, said communication means sends said ready signal to receive a data packet from an external device, and wherein if said data packet is received, said detection means compares said received data with each of said predetermined set of valid data packets such that if said data packet is valid, said detection means keeps said switch enabled, and if said data packet is invalid or if said data packet is not received, said detection means disables said switch for a predetermined period of time.

2. The circuit of claim 1, wherein said data concentrator communication means comprises a synchronous high speed receiver transmitter, said high speed receiver transmitter comprising:

means for transmitting binary data wherein said binary data includes said data packet and said indication signal; and

means for receiving binary data wherein said binary data includes said ready signal, wherein said binary data transmitting means transmits said indication signal, and transmits said data packet after said binary data receiving means receives said ready signal.

3. The circuit of claim 1, wherein said host adapter communication means comprises a synchronous high speed receiver transmitter, said high speed receiver transmitter comprising:

means for receiving binary data wherein said binary data includes said data packet and said indication signal; and

means for transmitting binary data wherein said binary data includes said ready signal, wherein said binary data receiving means receives said indication signal, and receives said data packet after said binary data transmitting means transmits said ready signal.

4. The circuit of claim 1, wherein said switch includes a logic controlled relay.

5. The circuit of claim 1, wherein said detector means further comprises memory wherein said predetermined set of valid data packets is stored in said memory, and a microprocessor coupled to said memory, said host adapter communication means and said switch.