EP0368055A2
Expired / Lapsed
EP
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Method for sending a plurality of data channels over a single communications line
Assignee: Hayes Microcomputer Products Inc
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Filing: 1989-10-19
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Granted: —
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Expires: 2009-10-19
Abstract
Abstract A method for communicating with a plurality of hosts connected to an X.25 network and for selectably using a character as a control character or a data character. Each character received from the X.25 network is inspected to determine if it is one of a set of reserved characters. If so, the character is encoded before being sent to its final destination. Data intended for the X.25 network is inspected for the presence of a predetermined control character. If the control character is present, the next character is inspected to determine whether it is a command character or an encoded data character. If this next character is an encoded data character, it is decoded and provided to the X.25 network. If this next character is a command character, then the command is executed. The method allows the use of any character as either a command character or data character. Data transfer between the DTE and DCE is assigned a PAD and a virtual channel number which corresponds to a particular host on the X.25 network. The channel number may, but need not, be the same as the X.25 device address for that host. The method therefore allows the DTE and DCE to simultaneously communicate with a plurality of X.25 hosts over a single telephone line or physical transmission link.
Inventors
- 👤 Richard J. Burton
- 👤 John A. Iii Dr. Copeland
- 👤 John W. Jerrim
- 👤 Toby L. Nixon
- 👤 Martin H. Sauser, Jr.
- 👤 Robert E. Weatherford, Jr.
- 👤 Larry D. Becker
- 👤 David F. Strawn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 18:41
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/40
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
227 words
In a communications system including a first device, a plurality of host devices connected to a network node, and a second device interposed between said first device and said network node, each said host device having a predetermined address on said network node, a method for allowing said first device to conduct simultaneous communications with said plurality of host devices, characterized by: a first device procedure comprising the steps of: sending a first channel number corresponding to a first said host to said second device; sending data for said first host to said second device; sending a next channel number corresponding to a next said host to said second device; and sending data for said next host to said second device; and a second device procedure comprising the steps of: maintaining a correlation table between channel numbers and predetermined addresses for said host devices; maintaining a plurality of packet assembler-disassembler functions (PADs); receiving said first channel number; generating said predetermined address for said first host; sending said predetermined address to said network node; processing said data through a first said PAD; sending said processed data to said network node; receiving said second channel number; generating said predetermined address for said second host; sending said predetermined address to said network node; processing said data through a second said PAD; and sending said processed data to said network node.
Claim 2
Dependent Claim
227 words
In a communications system including a first device, a plurality of host devices connected to a network node, and a second device interposed between said first device and said network node, each said host device having a predetermined address on said network node, a method for allowing said first device to conduct simultaneous communications with said plurality of host devices, characterized by: a first device procedure comprising the steps of: sending a first channel number corresponding to a first said host to said second device; sending data for said first host to said second device; sending a next channel number corresponding to a next said host to said second device; and sending data for said next host to said second device; and a second device procedure comprising the steps of: maintaining a correlation table between channel numbers and predetermined addresses for said host devices; maintaining a plurality of packet assembler-disassembler functions (PADs); receiving said first channel number; generating said predetermined address for said first host; sending said predetermined address to said network node; processing said data through a first said PAD; sending said processed data to said network node; receiving said second channel number; generating said predetermined address for said second host; sending said predetermined address to said network node; processing said data through a second said PAD; and sending said processed data to said network node.
Claim 3
Dependent Claim
32 words
The method of Claim 1 wherein each first device step of sending a said channel number comprises: sending a first predetermined character; and sending a second character corresponding to said channel number.
Claim 4
Dependent Claim
71 words
The method Claim 2 wherein each first device step of sending data comprises: inspecting each data character of said data; if a said data character is not included in a predetermined set of characters then sending said data character; and if said data character is included in said predetermined set then generating a replacement character corresponding to said data character and sending said first predetermined character followed by said replacement character.
Claim 5
Dependent Claim
19 words
The method of Claim 3 wherein said replacement character is an ASCII character having a value greater than 31.
Claim 6
Dependent Claim
114 words
The method of Claim 1 wherein each second device step of processing said data comprises: inspecting each data character received from said first device; if said data character is not a first predetermined character then sending said data character to said PAD; if said data character is said first predetermined character then inspecting a next data character; if said next data character is not included in a set of replacement characters then processing said next data character as control information; and if said next data character is included in said set of replacement characters then generating an original data character corresponding to said replacement character and sending said original data character to said PAD.
Claim 7
Dependent Claim
14 words
The method of Claim 5 wherein said control information comprises a said channel number.
Claim 8
Dependent Claim
25 words
The method of Claim 5 wherein each replacement character in said set of replacement characters is an ASCII character having a value greater than 31.
Claim 9
Dependent Claim
40 words
The method of Claim 5 wherein said second device has a buffer memory associated with each said channel number, and said control information instructs said second device to stop sending data for a specified channel number to said first device.
Claim 10
Dependent Claim
27 words
The method of Claim 8 wherein said control information further instructs said second device to resume sending data for said specified channel number to said first device.
Claim 11
Dependent Claim
54 words
The method of Claim 1 wherein, if said data is a break sequence, said first device procedure further comprises: determining a duration for said break sequence; generating a set of characters signifying said break sequence having said duration; and sending a first predetermined character followed by said set of characters to said second device.
Claim 12
Dependent Claim
107 words
The method of Claim 10 wherein each said second device step of processing said data further comprises: inspecting each data character received from said first device; if said data character is not a first predetermined character then sending said data character to said PAD; if said data character is said first predetermined character then inspecting a next data character; if said next data character does not signify a break sequence then processing said next data character as control information; and if said next data character signifies a break sequence then sending to said network node a break sequence having a duration specified by said next data character.
Claim 13
Independent Claim
52 words
A method for allowing data terminal equipment (DTE) to access, through data communications equipment (DCE), a plurality of hosts connected to a predetermined node, characterized by the steps of: causing said DCE to access said predetermined node; establishing a first virtual channel number (VCN) for communications between said DTE and said DCE;
Claim 14
Independent Claim
52 words
A method for allowing data terminal equipment (DTE) to access, through data communications equipment (DCE), a plurality of hosts connected to a predetermined node, characterized by the steps of: causing said DCE to access said predetermined node; establishing a first virtual channel number (VCN) for communications between said DTE and said DCE;
Claim 15
Dependent Claim
83 words
establishing a first logical channel number (LCN) for communications between said DCE and a first host of said plurality of hosts; establishing a second VCN for communications between said DTE and said DCE; establishing a second LCN for communications between said DCE and a second host of said plurality of hosts; maintaining a correlation table between each said VCN and a corresponding LCN; and changing said VCN and said LCN in concordance whenever said DTE accesses a said host having a different LCN.
Claim 16
Dependent Claim
83 words
establishing a first logical channel number (LCN) for communications between said DCE and a first host of said plurality of hosts; establishing a second VCN for communications between said DTE and said DCE; establishing a second LCN for communications between said DCE and a second host of said plurality of hosts; maintaining a correlation table between each said VCN and a corresponding LCN; and changing said VCN and said LCN in concordance whenever said DTE accesses a said host having a different LCN.
Claim 17
Dependent Claim
54 words
The method of Claim 12 and further comprising: establishing a plurality of virtual channel numbers and a plurality of corresponding logical channel numbers; and maintaining said correlation table between each said virtual channel number of said plurality of virtual channel numbers and each said logical channel number of said plurality of logical channel numbers.
References Cited (Backward Citations)
No citation records indexed.
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