Patent ID: 6032209
Filing Date: 2000-02-29
Classification: G06F

Abstract:
A system for a hot-swappable point-to-point connection between a high speed transmitter on a first card and a high speed receiver on a second card, the transmitter being disabled if the transmitter output is not connected to a fixed voltage through resistive elements, the receiver disabled if the receiver input is not biased to a preset voltage, the first card and the second card insertable into a backplane, the backplane forming the connection between the transmitter and the receiver, the system comprising:a first power indicator on the first card connected to the backplane when the first card is inserted in the backplane, the power indicator operable to assert a first power signal when power is applied to the first card;a second power indicator on the second card connected to the backplane when the second card is inserted in the backplane, the power indicator operable to assert a second power signal when power is applied to the second card;a first switch on the first card connecting the transmitter output to a fixed voltage through at least one resistive element, the first switch having a first control input connected to the backplane when the first card is inserted in the backplane, the first switch operable to enable the transmitter when the first control input is asserted and to disable the transmitter when the first control input is unasserted;a second switch on the second card connected to a bias network, the bias network providing a bias voltage to the input of the receiver, the second switch having a second control input connected to the backplane when the second card is inserted in the backplane, the second switch operable to enable the receiver when the second control input is asserted and to disable the receiver when the second control input is unasserted by changing the output voltage of the bias network;a first connection through the backplane forming a first path between the first card and the second card, the first path connecting the first power indicator to the second control input when the first card and the second card are inserted in the backplane; anda second connection through the backplane forming a second path between the first card and the second card, the second path connecting the second power indicator to the first control input when the first card and the second card are inserted in the backplane;wherein the first control input is unasserted if the first card is inserted in the backplane and the second card is not inserted in the backplane, thereby disabling the transmitter when the transmitter is not connected to the receiver; andwherein the second control input is unasserted if the second card is inserted in the backplane and the first card is not inserted in the backplane, thereby disabling the receiver when the transmitter is not connected to the receiver.