Method and system for automatically determining data communication device type and corresponding transmission rate

• US 5,491,720 A
• Filed: 05/21/1992
• Issued: 02/13/1996
• Est. Priority Date: 05/21/1992
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Zevin, William M., Ziegenhain, Karl-Heinz, Linger, Judith M., Mandalia, Baiju D., Davis, Gordon T., Sinibaldi, John C.
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US07/887,433
• Time in Patent Office: 1,363 Days
• Field of Search: 375/222, 375/225, 375/377, 370/79, 370/84, 370/110.1, 370/85.13, 371/5.5, 371/32, 379/97
• US Class Current: 375/222
• CPC Class Codes: H04L 25/0262 Arrangements for detecting the data rate of an incoming signal
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A method and system in a data communications system for automatically determining a data communication device type and a transmission speed associated with the data communication device type. An incoming communication is detected on a transmission line, and transmit and receive hardware are connected to the transmission line. Next, a sequence of different signals in either a first communication protocol or a second communication protocol are transmitted from a first data communication device via a transmission line. The transmission line is then monitored for a response signal from a second data communication device. The response signal is initiated from the second data communication device in response to receipt of a particular signal within the transmitted sequence of different signals. Utilizing the relationship between the response signal and the transmitted sequence of different signals, a data communication device type and transmission speed are determined, and data communications may then be established between the first data communication device and the second data communication device at an optimal transmission speed.

Claims

1. A method in a data communication system for automatically determining a data communication device type and a transmission speed associated with said data communication device type, wherein said data communication system comprises a first data communication device and at least a second data communication device couplable to said first data communication device over a transmission line, said method comprising the steps of:

initiating transmission in a first communication protocol of a sequence of different signals from said first data communication device via said transmission line at predetermined intervals;

monitoring said transmission line for an occurrence of a response signal from said second data communication device;

initiating the response signal from said second data communication device in response to receipt of a particular signal within said sequence of different signals;

utilizing a relationship between said occurrence of said response signal and the transmission of said sequence of different signals to determine the data communication device type and the transmission speed for said second data communication device, wherein data communications may be established between said first data communication device and said second data communication device at an optimal transmission speed.

2. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 1, wherein said transmission of said sequence of different signals further includes transmission of a sequence of different signals in a second communications protocol.

3. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 2, wherein said first data communication device is adapted to receive one of a plurality of channel requests from one of a plurality of associated data communication devices.

4. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 3, wherein said first data communication device comprises a modem.

5. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 4, wherein said first communication protocol comprises a frequency-shift keying protocol.

6. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 5, wherein said second communication protocol comprises a phase-shift keying protocol.

7. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 1, further comprising the step of terminating communications between said first data communication device and said second data communication device in response a failure to monitor the response signal within a select period of time.

8. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 1, further comprising the step of interrupting said transmission of said sequence of different signals in response to receiving the response signal from said second data communication device.

9. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 8, wherein said second data communication device comprises a modem.

10. The method in the data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 1, wherein said step of utilizing the relationship between the response signal and the transmission of said sequence of different signals comprises determining a temporal relationship between the response signal and the transmission of said sequence of different signals to determine the data communication device type and the transmission speed for said second data communication device.

11. A data communication system for automatically determining a data communication device type and a transmission speed associated with said data communication device type, wherein said data communication system comprises:

a first data communication device and at least a second data communication device couplable to said first data communication device over a transmission line;

means for initiating transmission in a first communication protocol of a sequence of different signals from said first data communication device via said transmission line at predetermined intervals;

means for monitoring said transmission line for an occurrence of a response signal from said second data communication device;

means for initiating the response signal from said second data communication device in response to receipt of a particular signal within said sequence of different signals; and

means for utilizing a relationship between said occurrence of said response signal and the transmission of said sequence of different signals to determine the data communication device type and the transmission speed for said second data communication device, wherein data communications may be established between said first data communication device and said second data communication device at an optimal transmission speed.

12. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 11, wherein said transmission of said sequence of different signals further includes transmission of a sequence of different signals in a second communications protocol.

13. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 12, wherein said first data communication device is adapted to receive one of a plurality of channel requests from One Of a plurality of associated data communication devices.

14. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 13, wherein said first data communication device comprises a modem.

15. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 14, wherein said first communication protocol comprises a frequency-shift keying protocol.

16. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 15, wherein said second communication protocol comprises a phase-shift keying protocol.

17. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 11, further comprising means for terminating communications between said first data communication device and said second data communication device in response a failure to monitor the response signal within a select period of time.

18. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 11, further comprising means for interrupting said transmission of said sequence of different signals in response to receiving the response signal from said second data communication device.

19. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 18, wherein said second data communication device comprises a modem.

20. The data communication system for automatically determining the data communication device type and the transmission speed associated with said data communication device type according to claim 11, wherein said means for utilizing the relationship between the response signal and the transmission of said sequence of different signals comprises means for determining a temporal relationship between the response signal and the transmission of said sequence of different signals to determine the data communication device type and the transmission speed for said second data communication device.