Serial communications interface that supports multiple interface standards

• US 5,737,364 A
• Filed: 02/18/1994
• Issued: 04/07/1998
• Est. Priority Date: 02/18/1994
• Status: Expired due to Fees

• Current Assignee: Telebit Corp. (Cisco Systems, Inc.)
• Original Assignee: Telebit Corp. (Cisco Systems, Inc.)
• Inventors: Smader, Scott Kingsley, Cohen, Gary L.
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): NGUYEN, ANH-VINH THI
• Application Number:
  US08/198,448
• Time in Patent Office: 1,509 Days
• Field of Search: 375/377, 375/220, 395/275, 395/325, 364/900, 370/14, 370/17, 370/60.1, 370/119, 333/25, 333/145
• US Class Current: 375/220
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 69/323 in the physical layer [OSI layer 1]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

An interface for connecting data-terminal-equipment (DTE) to a range of data-communication-equipment (DCE) using a multiplicity of interface standards is provided. The interface includes a DTE panel connector and a plurality of line drivers and receivers and associated electronics to select predetermined ones of the plurality of receivers and drivers for use the DTE when cables having a predetermined configuration, corresponding to the supported interface standards, are attached. The cables connect the appropriate drivers and receivers of the DTE with the corresponding receivers and drivers, respectively, of the DCE. Additionally the cables also contain termination devices and a selection mechanism to select which drivers and receivers are to be used by the DTE to communicate with the receivers and drivers respectively, being used by the DCE.

Claims

1. A DTE communications system coupled between a DTE and a DCE for supporting a plurality of interface communications standards, said DTE communications system comprising:

a DTE interface having a first connector and interface electronics comprising;

at least two receivers, each of said at least two receivers having at least one input terminal in electrical communication with said first connector and each of said at least two receivers having an output terminal; and

a selection circuit comprising a multiplexer having a control terminal, an output terminal coupled to said DTE, a first input terminal in electrical communication with said output terminal of one of said at least two receivers, and a second input terminal in electrical communication with said output terminal of the other of said at least two receivers and a comparator having a first input coupled to said first connector, a second input and an output coupled to said control terminal of said multiplexer and at which a selection signal is provided; and

a DTE interface cable assembly comprising a second connector for mating with said first connector, and an identification device in electrical communication with said second connector,

said identification device operative to provide a signal to said first input of said comparator to identify which of said plurality of interface standards is supported by said DTE interface cable assembly, wherein said selection signal is generated by said comparator in response to said signal provided by said identification device and coupled to said first input of said comparator as a result of the mating of said first and second connectors,

said selection circuit operative to electrically connect the output terminal of a selected one of said at least two receivers to said output terminal of said multiplexer in response to said selection signal applied to said control terminal of said multiplexer.

2. A DTE communications interface coupled between a DTE and a DCE for supporting a plurality of interface communications standards, said DTE interface comprising:

a connector;

interface electronics comprising at least two receivers, each of said at least two receivers having an output terminal, and having an input terminal in electrical communication with said connector; and

a selection circuit comprising a multiplexer having a control terminal, an output terminal coupled to said DTE, a first input terminal in electrical communication with an output terminal of one of said at least two receivers, and a second input terminal in electrical communication with the output terminal of the other of said at least two receivers and a comparator having a first input coupled to said connector, a second input and an output coupled to said control terminal of said multiplexer at which a selection signal is provided;

said selection circuit operative to electrically connect the output of a selected one of said at least two receivers to the output of said multiplexer in response to said selection signal applied to said control terminal of said multiplexer.

3. The DTE communications interface of claim 2 wherein one of said two receivers is a balanced differential receiver and the other of said two receivers is a single-ended receiver.

4. The DTE communications interface of claim 3 wherein said multiplexer comprises programmable array logic.

5. The DTE communications interface of claim 2 wherein said comparator comprises a voltage comparator.

6. A DTE interface cable assembly coupled between a DTE and a DCE comprising:

a cable connector for mating with a panel connector; and

an identification device in electrical communication with said cable connector,

said identification device operative to provide a signal to identify which of a plurality of interface standards is supported by said DTE interface cable assembly, said identification device applying said signal to a control terminal of a multiplexer of a selection circuit of a DTE interface,

said selection circuit comprising said multiplexer having said control terminal, an output terminal coupled to said DTE, a first input terminal in electrical communication with an output terminal of one of at least two receivers of said DTE interface and a second input terminal in electrical communication with the output terminal of the other of said at least two receivers and a comparator having a first input responsive to said signal provided by said identification device, a second input and an output coupled to said control terminal of said multiplexer at which a selection signal is provided, wherein said selection signal is generated by said comparator in response to said signal provided by said identification device and coupled to said first input of said comparator as a result of the mating of said panel connector and said cable connector;

said selection circuit operative to electrically connect the output of a selected one of said at least two receivers to the output of said multiplexer in response to said selection signal applied to said control terminal of said multiplexer.

7. The DTE interface cable assembly of claim 6 further comprising at least one termination resistor in electrical communication with said cable connector.

8. The DTE interface cable assembly of claim 6 wherein said identification device comprises a resistor in electrical communication with said cable connector.

9. The DTE interface cable assembly of claim 6 wherein said identification device comprises a wire in electrical communication with said cable connector.

10. A DTE communications system coupled between a DTE and a DCE for supporting a plurality of interface communications standards, said DTE communications system comprising:

a DTE interface having a first connector having a plurality of contacts, and interface electronics having a plurality of receiver pairs and a selection circuit, each receiver of said receiver pair having an input terminal in electrical communication with a respective one of said plurality of contacts and an output terminal in electrical communication with an input terminal of a multiplexer of said selection circuit, said selection circuit comprising said multiplexer also having a control terminal and an output terminal coupled to said DTE and a comparator having a first input coupled to a respective one of said plurality of contacts, a second input and an output coupled to said control terminal of said multiplexer and at which a selection signal is provided; and

a DTE interface cable assembly having a second connector having a plurality of contacts, and an identification device in electrical communication with at least one of said contacts of said plurality of contacts of said second connector, said identification device operative to provide a signal to said first input of said comparator to identify which of said plurality of interface standards is supported by said DTE interface cable assembly, wherein said selection signal is generated by said comparator in response to said signal provided by said identification device and coupled to said first input of said comparator as a result of the mating of said first and second connectors,

said second connector for mating with said first connector and each of said plurality of contacts of said second connector for electrical communication with a respective one of said plurality of contacts of said first connector,

said selection circuit operative to electrically connect a selected one of said pair of said plurality of receiver pairs to said multiplexer output terminal in response to said selection signal applied to said control terminal of said multiplexer.

11. The DTE communications system of claim 10 wherein said DTE interface cable assembly further comprises at least one termination resistor connected between two of said contacts of said plurality of contacts of said second connector.

12. The DTE communications system of claim 10 wherein said identification device comprises a resistor connected between two of said contacts of said plurality of contacts of said second connector.

13. The DTE communications system of claim 10 wherein said identification device comprises a wire connected between two of said contacts of said plurality of contacts of said second connector.

14. The DTE communications system of claim 10 wherein said identification device comprises an open contact of said plurality of contacts of said second connector.

15. The DTE communications system of claim 10 wherein each said receiver pair comprises a balanced differential receiver and a single-ended receiver.

16. The DTE communications system of claim 15 wherein said multiplexer comprises programmable array logic.

17. The DTE communications system of claim 10 wherein said comparator comprises a voltage comparator.

18. A DTE communications system coupled between a DTE and a DCE for supporting a plurality of interface communications standards, said DTE communications system comprising:

a DTE interface having a first connector and interface electronics including at least two receivers in electrical communication with said first connector, and a selection circuit comprising a multiplexer having a first input terminal in communication with one of said at least two receivers, a second input terminal in communication with the other of said at least two receivers, an output terminal coupled to said DTE, and a control terminal and a comparator having a first input coupled to said first connector, a second input and an output coupled to said control terminal of said multiplexer and at which a selection signal is provided; and

a DTE interface cable assembly having a second connector for mating with said first connector, and an identification device in electrical communication with said second connector,

said identification device operative to provide an analog signal to said first input of said comparator to identify which of said plurality of interface standards is supported by said DTE interface cable assembly, wherein said selection signal is generated by said comparator in response to said analog signal provided by said identification device and coupled to said first input of said comparator as a result of the mating of said first and second connectors,

said selection circuit operative to electrically connect a selected one of said at least two receivers to said output terminal of said multiplexer in response to said selection signal applied to said control terminal of said multiplexer.

19. A DTE communications interface coupled between a DTE and a DCE for supporting a plurality of interface communications standards, said DTE interface comprising:

a connector;

interface electronics comprising at least two receivers, each of said at least two receivers having an output terminal, and having an input terminal in electrical communication with said connector; and

a selection circuit comprising a multiplexer having a control terminal, an output terminal coupled to said DTE, a first input terminal in electrical communication with the output terminal of one of said at least two receivers, and a second input terminal in electrical communication with the output terminal of the other of said at least two receivers and a comparator having a first input coupled to said connector, a second input and an output coupled to said control terminal of said multiplexer at which a selection signal is provided;

said selection circuit operative to electrically connect the output of a selected one of said at least two receivers to the output of said multiplexer in response to said selection signal applied to said control terminal of said multiplexer.

20. A DTE interface cable assembly coupled between a DTE and a DCE comprising:

a cable connector for mating with a panel connector of a DTE interface; and

an identification device in electrical communication with said cable connector,

said identification device operative to provide an analog signal to identify which of a plurality of interface standards is supported by said DTE interface cable assembly, said identification device applying said analog signal to a control terminal of a multiplexer of a selection circuit of said DTE interface,

said selection circuit comprising said multiplexer having said control terminal, an output terminal coupled to said DTE, a first input terminal in electrical communication with an output terminal of one of at least two receivers of said DTE interface, and a second input terminal in electrical communication with the output terminal of the other of said at least two receivers of said DTE interface and a comparator having a first input responsive to said analog signal provided by said identification device, a second input and an output coupled to said control terminal of said multiplexer at which a selection signal is provided, wherein said selection signal is generated by said comparator in response to said analog signal provided by said identification device and coupled to said first input of said .comparator as a result of the mating of said panel connector and said cable connector;

said selection circuit operative to electrically connect the output of a selected one of said at least two receivers to the output of said multiplexer in response to said selection signal applied to said control terminal of said multiplexer.

21. A DTE communications system coupled between a DTE and a DCE for supporting a plurality of interface communications standards, said DTE communications system comprising:

a DTE interface having a first connector having a plurality of contacts, and interface electronics having a plurality of receiver pairs and a selection circuit, each receiver of said receiver pair having an input terminal in electrical communication with a respective one of said plurality of contacts and an output terminal in electrical communication with an input terminal of a multiplexer of said selection circuit, said selection circuit comprising said multiplexer also having a control terminal and an output terminal coupled to said DTE and a comparator having a first input coupled to a respective one of said plurality of contacts, a second input and an output coupled to said control terminal of said multiplexer and at which a selection signal is provided; and

a DTE interface cable assembly having a second connector having a plurality of contacts, and an identification device in electrical communication with at least one of said contacts of said plurality of contacts of said second connector, said identification device operative to provide an analog signal to said first input of said comparator to identify which of said plurality of interface standards is supported by said DTE interface cable assembly, wherein said selection signal is generated by said comparator in response to said analog signal provided by said identification device and coupled to said first input of said comparator as a result of the mating of said first and second connectors,

said second connector for mating with said first connector and each of said plurality of contacts of said second connector for electrical communication with a respective one of said plurality of contacts of said first connector,

said selection circuit operative to electrically connect a selected one of said pair of said plurality of receiver pairs to said multiplexer output terminal in response to said selection signal applied to said control terminal of said multiplexer.