Integrated modem which employs a host processor as its controller
DCFirst Claim
1. In a computer having a host processor that is responsive to a communications program in a program memory to generate and receive control and data characters on an internal bus for use in communicating with other computers, a communications system which employs said host processor as a virtual controller, comprising:
- a modem including means for receiving data characters from said internal bus and transmitting them onto a telephone line and for receiving data characters from said telephone line and placing them on said internal bus;
interface means, including at least one register for receiving control and data characters generated by said host processor in response to said communications program, for generating a predetermined interrupt request indicative of receipt of said control and data characters;
a modem driver program stored in said program memory and containing instructions for configuring said modem to carry out operations commanded by said communications program and controlling the operation of said modem to transfer data between the telephone line and said interface means; and
control means responsive to the generation of said predetermined interrupt request by said interface means for causing said host processor to access said modem driver program stored in said program memory and to control said modem in accordance with the instructions contained in said modem driver program.
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Accused Products
Abstract
An embedded modem that does not require a dedicated controller and operates with existing computer to interpret new and redefined communications interrupt requests. In response to an interrupt request, the control of the processor is transferred from the communications software to a driver program stored in the main memory for the processor. Under the operation of the driver program, the processor interprets control characters and causes the appropriate commands to be carried out in the modem. Once these commands have been processed, the control of the processor reverts back to the communications program. The processor thereby functions as a virtual controller that is interpreted to be an external controller by the communications program.
98 Citations
30 Claims
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1. In a computer having a host processor that is responsive to a communications program in a program memory to generate and receive control and data characters on an internal bus for use in communicating with other computers, a communications system which employs said host processor as a virtual controller, comprising:
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a modem including means for receiving data characters from said internal bus and transmitting them onto a telephone line and for receiving data characters from said telephone line and placing them on said internal bus; interface means, including at least one register for receiving control and data characters generated by said host processor in response to said communications program, for generating a predetermined interrupt request indicative of receipt of said control and data characters; a modem driver program stored in said program memory and containing instructions for configuring said modem to carry out operations commanded by said communications program and controlling the operation of said modem to transfer data between the telephone line and said interface means; and control means responsive to the generation of said predetermined interrupt request by said interface means for causing said host processor to access said modem driver program stored in said program memory and to control said modem in accordance with the instructions contained in said modem driver program. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for controlling a modem in a computer having a host processor, comprising the steps of:
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operating the host processor of the computer under control of a communications program to generate commands relating to transfer of data between the computer and a communications link; generating an interrupt request to said host processor to indicate when information has been received by the modem; - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A modem circuit for transferring information between a communication link and a computer having a host processor, comprising:
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a modulator for transmitting information from the host processor onto the communication link; a demodulator for receiving information on the communication link; a transmit hold register for receiving characters generated by the host processor and providing them to said modulator; means for generating a first interrupt request to the host processor when a character has been placed in the transmit hold register by the host processor; a receive hold register for receiving characters that are to be provided to the host processor from said demodulator; and means for generating a second interrupt request to the host processor when said host processor retrieves characters from said receive hold register. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method for controlling a modem in a computer having a host processor, comprising the steps of:
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operating the host processor of the computer under control of a communications program to generate commands relating to transfer of data between the computer and a communications line; generating an interrupt request to said host processor to indicate when information has been received by the modem; transferring control of the host processor from the communications program to a modem driver program in response to the generation of the interrupt request; determining, under control of the modem driver program, whether the information received by the modem requires servicing by the communications program or by the modem driver program; returning control of the host processor to the communications program if the information is to be serviced by the communications program; and maintaining control of the host processor by the driver program when the information is to be serviced by the driver program and retrieving said information at the host processor. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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Specification