Communication protocol for half-duplex traffic
First Claim
1. A method for arranging an infra-red data transfer link between a first device and a second device, said first device comprising a first infra-red transmitter means and a first infra-red receiver means and said second device comprising a second infra-red transmitter means and a second infra-red receiver means, wherein, after a collision, in which collision said first and second transmitter means transmit simultaneously, said first device transmits the message (CM1) involved in said collision again (CM1'"'"') after elapse of a predetermined first period of time and said second device transmits the message (CM2) involved in said collision again (CM2'"'"') after elapse of a predetermined second period of time, and said first and second periods of time are of different duration;
- andthe method further comprises placing at least one of said first and said second devices in a sleep mode during an idle mode of said data transfer link, and waking the receiver means of said one of said first and said second devices during successive intervals of time for receipt of a possible wake signal from the other of said first and said second devices, thereby to wake said one of said first and said second of said devices to receive a transfer of data from said other of said first and said second devices.
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Accused Products
Abstract
The invention relates to a communication protocol with the aid of which a half-duplex type data transfer link is arranged between two devices, advantageously a mobile telephone (3) and a data adapter (2) in a computer (1). The link can be in a transfer mode, when data being transferred and control messages (CM) are passed between the devices, or an idle mode, when control messages (CM1, CM2, CM1'"'"', CM2'"'"') are passed between the devices. In idle mode the timing of the transmission of control messages is free and if two messages (CM1, CM2) collide, i.e. are transmitted simultaneously, they are re-transmitted (CM1'"'"', CM2'"'"') after time intervals of different duration. In transfer mode mobile telephone (3) regularly transmits a single frame (DATA) decoded by it and immediately before that a possible control message (CM). Data adapter (2) transmits a frame (DATA) every time it receives a frame transmitted by the mobile telephone and immediately after trans-mitting the frame transmits a possible control message (CM). A device can be switched into a sleep mode, in which it receives only for a short time (T2) at regular intervals (T1). A device in sleep mode can be woken up by a wake-up signal.
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Citations
9 Claims
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1. A method for arranging an infra-red data transfer link between a first device and a second device, said first device comprising a first infra-red transmitter means and a first infra-red receiver means and said second device comprising a second infra-red transmitter means and a second infra-red receiver means, wherein, after a collision, in which collision said first and second transmitter means transmit simultaneously, said first device transmits the message (CM1) involved in said collision again (CM1'"'"') after elapse of a predetermined first period of time and said second device transmits the message (CM2) involved in said collision again (CM2'"'"') after elapse of a predetermined second period of time, and said first and second periods of time are of different duration;
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the method further comprises placing at least one of said first and said second devices in a sleep mode during an idle mode of said data transfer link, and waking the receiver means of said one of said first and said second devices during successive intervals of time for receipt of a possible wake signal from the other of said first and said second devices, thereby to wake said one of said first and said second of said devices to receive a transfer of data from said other of said first and said second devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Equipment for transfer of data by means of infra-red radiation between a first device and a second device, said first device comprising a first infra-red transmitter means and a first infra-red receiver means and said second device comprising a second infra-red transmitter means and a second infra-red receiver means;
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wherein the equipment further comprises in said first device a first delay means for re-transmitting a message subject to interference after elapse of a certain first period of time from its transmission and, in said second device, further comprises second delay means for re-transmitting a message subject to interference after elapse of a certain second period of time from its transmission, and said first and second delay means are so arranged that said first period of time is of a different duration from said second period of time; and wherein the equipment further comprises sleep means for placing at least one of said first and said second devices in a sleep mode during an idle mode of a data transfer link, said sleep means serving for waking the receiver means of said one of said first and said second devices during successive intervals of time for receipt of a possible wake signal from the other of said first and said second devices, thereby to wake said one of said first and said second of said devices to receive a transfer of data from said other of said first and said second devices.
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Specification