Method and apparatus of operating data communications equipment in command mode and autobauding

Claim 2

In a data communication system including data communication equipment receiving incoming command signals, said incoming command signals being provided by data terminal equipment at one of a plurality of data transfer rates, an incoming command signal comprising an autobauding prefix and a command character, the data communication equipment including a memory device, a microprocessor, and an output buffer for sending response signals to said data terminal equipment, a method for autobauding and processing incoming command signals, comprising the steps of: (a) sampling said incoming command signal at a fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; (b) storing said samples of said incoming command signal in bytes in said memory device; (c) transferring said samples of said incoming command signal directly from said memory device to said output buffer until at least a portion of said command character is detected; (d) autobauding in response to receipt of said autobauding prefix; (e) detecting the occurrence of each bit of the command character following said autobauding prefix by analyzing a center sample, in said memory device, of each bit in the command character and locating each subsequent bit by moving between said center samples in byte increments; (f) generating a response signal corresponding to said incoming command signal containing said detected command character; and (g) transferring said response signal from the microprocessor to said data terminal equipment directly through said output buffer; wherein said steps (a) through (e) are performed for a subsequent incoming command signal having a first data transfer rate before completion of operations (f) and (g) for a prior incoming command signal having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.

Claim 3

A data communication equipment for receiving an incoming command signal, said incoming command signal being provided by data terminal equipment at one of a plurality of data transfer rates, said incoming command signal comprising an autobauding prefix and a command character, said data communication equipment comprising: a high speed clock generating a sample clock signal, said sample clock signal having a fixed sampling frequency, said fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; sampling means responsive to said sample clock signal for taking samples of said incoming command signal; a memory device for storing said samples of said incoming command signal; a microprocessor, controlling said data communication equipment, and operating to: (a) transfer said samples of said incoming command signal from said sampling means to said memory device; (b) inspect said samples of said incoming command signal to detect a first predetermined transition of said incoming command signal; (c) inspect said samples of said incoming command signal to detect a second predetermined transition of said incoming command signal; (d) determine the number of samples of said incoming command signal between said first predetermined transition and said second predetermined transition; (e) determine the data transfer rate of said incoming command signal based upon said number of samples; (f) detect the occurrence of said autobauding prefix in said incoming command signal; (g) autobaud at said determined data transfer rate in response to detection of said autobauding prefix; (h) after detecting said autobauding prefix, detect the occurrence of said command character; and (i) generate a response signal corresponding to said incoming command signal containing said detected command character; wherein said microprocessor operates said data communication equipment in a single state while in command mode such that said microprocessor performs operations (a) through (g) for a current said command character having a first data transfer rate before said microprocessor has completed operations (h) and (i) for a previous said command character having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.

Claim 4

A data communication equipment for receiving an incoming command signal, said incoming command signal being provided by data terminal equipment at one of a plurality of data transfer rates, said incoming command signal comprising an autobauding prefix and a command character, said data communication equipment comprising: a high speed clock generating a sample clock signal, said sample clock signal having a fixed sampling frequency, said fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; sampling means responsive to said sample clock signal for taking samples of said incoming command signal; a memory device for storing said samples of said incoming command signal; a microprocessor, controlling said data communication equipment, and operating to: (a) transfer said samples of said incoming command signal from said sampling means to said memory device; (b) inspect said samples of said incoming command signal to detect a first predetermined transition of said incoming command signal; (c) inspect said samples of said incoming command signal to detect a second predetermined transition of said incoming command signal; (d) determine the number of samples of said incoming command signal between said first predetermined transition and said second predetermined transition; (e) determine the data transfer rate of said incoming command signal based upon said number of samples; (f) detect the occurrence of said autobauding prefix in said incoming command signal; (g) autobaud at said determined data transfer rate in response to detection of said autobauding prefix; (h) after detecting said autobauding prefix, detect the occurrence of said command character; and (i) generate a response signal corresponding to said incoming command signal containing said detected command character; wherein said microprocessor operates said data communication equipment in a single state while in command mode such that said microprocessor performs operations (a) through (g) for a current said command character having a first data transfer rate before said microprocessor has completed operations (h) and (i) for a previous said command character having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.

Claim 5

A data communication equipment for receiving an incoming command signal, said incoming command signal being provided by data terminal equipment at one of a plurality of data transfer rates, said incoming command signal comprising an autobauding prefix and a command character, said data communication equipment comprising: a high speed clock generating a sample clock signal, said sample clock signal having a fixed sampling frequency, said fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; sampling means responsive to said sample clock signal for taking samples of said incoming command signal; a memory device for storing said samples of said incoming command signal; a microprocessor, controlling said data communication equipment, and operating to: (a) transfer said samples of said incoming command signal from said sampling means to said memory device; (b) inspect said samples of said incoming command signal to detect a first predetermined transition of said incoming command signal; (c) inspect said samples of said incoming command signal to detect a second predetermined transition of said incoming command signal; (d) determine the number of samples of said incoming command signal between said first predetermined transition and said second predetermined transition; (e) determine the data transfer rate of said incoming command signal based upon said number of samples; (f) detect the occurrence of said autobauding prefix in said incoming command signal; (g) autobaud at said determined data transfer rate in response to detection of said autobauding prefix; (h) after detecting said autobauding prefix, detect the occurrence of said command character; and (i) generate a response signal corresponding to said incoming command signal containing said detected command character; wherein said microprocessor operates said data communication equipment to perform operations (a) through (g) for a subsequent incoming command signal having a first data transfer rate before completing operations (h) and (i) for a prior incoming command signal having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.

Claim 6

A data communication equipment for receiving an incoming command signal, said incoming command signal being provided by data terminal equipment at one of a plurality of data transfer rates, said incoming command signal comprising an autobauding prefix and a command character, said data communication equipment comprising: a high speed clock generating a sample clock signal, said sample clock signal having a fixed sampling frequency, said fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; sampling means responsive to said sample clock signal for taking samples of said incoming command signal; a memory device for storing said samples of said incoming command signal; a microprocessor, controlling said data communication equipment, and operating to: (a) transfer said samples of said incoming command signal from said sampling means to said memory device; (b) inspect said samples of said incoming command signal to detect a first predetermined transition of said incoming command signal; (c) inspect said samples of said incoming command signal to detect a second predetermined transition of said incoming command signal; (d) determine the number of samples of said incoming command signal between said first predetermined transition and said second predetermined transition; (e) determine the data transfer rate of said incoming command signal based upon said number of samples; (f) detect the occurrence of said autobauding prefix in said incoming command signal; (g) autobaud at said determined data transfer rate in response to detection of said autobauding prefix; (h) after detecting said autobauding prefix, detect the occurrence of said command character; and (i) generate a response signal corresponding to said incoming command signal containing said detected command character; wherein said microprocessor operates said data communication equipment to perform operations (a) through (g) for a subsequent incoming command signal having a first data transfer rate before completing operations (h) and (i) for a prior incoming command signal having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.

Claim 7

In a data communication system including data communication equipment receiving incoming command signals provided by data terminal equipment, said incoming command signal being provided by said data terminal equipment at one of a plurality of data transfer rates, a said incoming command signal comprising an autobaud prefix and a command character, a method for autobauding by said data communication equipment, said method comprising the steps of: (a) receiving said incoming command signal; (b) sampling said incoming command signal at a fixed sampling frequency to provide samples of said incoming command signal, said fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; (c) storing said samples of said incoming command signal in a memory device; (d) inspecting said samples of said incoming command signal to detect a first predetermined transition of said incoming command signal; (e) inspecting said samples of said incoming command signal to detect a second predetermined transition of said incoming command signal; (f) determining the number of samples of said incoming command signal between said first predetermined transition and said second predetermined transition; (g) determining the data transfer rate of said incoming command signal based upon said number of samples; (h) detecting the occurrence of said autobaud prefix in said incoming command signal; (i) autobauding at said determined data transfer rate in response to said detected autobaud prefix; (j) after detecting said autobaud prefix, detecting the occurrence of said command character in said incoming command signal; and (k) generating a response signal corresponding to said incoming command signal containing said detected command character; wherein said steps (a) through (i) are performed for a subsequent incoming command signal having a first data transfer rate before completion of operations (j) and (k) for a prior incoming command signal having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.

Claim 8

In a data communication system including data communication equipment receiving incoming command signals provided by data terminal equipment, said incoming command signal being provided by said data terminal equipment at one of a plurality of data transfer rates, a said incoming command signal comprising an autobaud prefix and a command character, a method for autobauding by said data communication equipment, said method comprising the steps of: (a) receiving said incoming command signal; (b) sampling said incoming command signal at a fixed sampling frequency to provide samples of said incoming command signal, said fixed sampling frequency being a predetermined integer multiple of the highest data transfer rate of said plurality of data transfer rates; (c) storing said samples of said incoming command signal in a memory device; (d) inspecting said samples of said incoming command signal to detect a first predetermined transition of said incoming command signal; (e) inspecting said samples of said incoming command signal to detect a second predetermined transition of said incoming command signal; (f) determining the number of samples of said incoming command signal between said first predetermined transition and said second predetermined transition; (g) determining the data transfer rate of said incoming command signal based upon said number of samples; (h) detecting the occurrence of said autobaud prefix in said incoming command signal; (i) autobauding at said determined data transfer rate in response to said detected autobaud prefix; (j) after detecting said autobaud prefix, detecting the occurrence of said command character in said incoming command signal; and (k) generating a response signal corresponding to said incoming command signal containing said detected command character; wherein said steps (a) through (i) are performed for a subsequent incoming command signal having a first data transfer rate before completion of operations (j) and (k) for a prior incoming command signal having a second data transfer rate, said second data transfer rate being different than said first data transfer rate.