Apparatus for unit control and presence detection

Claim 2

Apparatus for using a signal line that communicates an operating signal from one electronic unit to another electronic unit to also detect the connection of the another electronic unit to the signal line, comprising: a driver element, forming a part of the one electronic unit, and having an output that communicates the operating signal to the signal line, the driver element operating to have the output placed in a high impedance state; a buffer element coupled to the signal line to provide a sense signal indicative of connection of the another electronic unit by presence of a predetermined voltage level on the signal line; and an impedance coupled to a voltage to apply the predetermined voltage level to the signal line when the driver element output is placed in the high impedance state.

Claim 3

The apparatus of claim 1, wherein the impedance includes a first impedance element coupled between the voltage and the signal line.

Claim 4

The apparatus of claim 2, wherein the voltage is positive.

Claim 5

The apparatus of claim 2, wherein the impedance includes a second impedance element that couples the signal line to a voltage potential.

Claim 6

The apparatus of claim 4, wherein the voltage potential is less than the voltage.

Claim 7

The apparatus of claim 5, wherein the voltage potential is a ground potential.

Claim 8

The apparatus of claim 2, wherein the first impedance element is a resistance.

Claim 9

The apparatus of claim 2, wherein the first impedance element is a resistance of approximately one megohm.

Claim 10

The apparatus of claim 4, wherein the first and the second impedance elements are each a resistance.

Claim 11

The apparatus of claim 4, wherein the one, the first, and the second impedances are resistances.

Claim 12

The apparatus of claim 4, wherein the first impedance element is a resistance having a value of approximately one megohm and the second impedance element is a resistance having a value of approximately ten Kohms.

Claim 13

The apparatus of claim 1, wherein the predetermined voltage level is a positive voltage.

Claim 14

Apparatus for using a signal line to communicate an operating signal from a first component coupled to the signal line to a second electronic component coupled to the signal line and to provide a sense signal indicative of the second component not being coupled to the signal line, the apparatus comprising: the first component including a driver element and a receiver, the driver element having an output that communicates the operating signal to the signal line, the driver element operating to have the output selectively placed in a high impedance state; the buffer element being coupled to the signal line to provide the sense signal indicative of the second component not being coupled to the signal line when a predetermined voltage level is present on the signal line; and a first impedance and a second impedance coupled to the signal line for applying the predetermined voltage level thereto when the driver element output is placed in a high impedance state, the first impedance being coupled to a first voltage, and the second impedance being in series connection with the first impedance and coupled to a second voltage that is less in magnitude than the first voltage.

Claim 15

Apparatus for using a signal line to communicate an operating signal from a first component coupled to the signal line to a second electronic component coupled to the signal line and to provide a sense signal indicative of the second component not being coupled to the signal line, the apparatus comprising: the first component including a driver element and a receiver, the driver element having an output that communicates the operating signal to the signal line, the driver element operating to have the output selectively placed in a high impedance state; the buffer element being coupled to the signal line to provide the sense signal indicative of the second component not being coupled to the signal line when a predetermined voltage level is present on the signal line; and a first impedance and a second impedance coupled to the signal line for applying the predetermined voltage level thereto when the driver element output is placed in a high impedance state, the first impedance being coupled to a first voltage, and the second impedance being in series connection with the first impedance and coupled to a second voltage that is less in magnitude than the first voltage.

Claim 16

The apparatus of claim 13, wherein the first impedance is a resistance.

Claim 17

The apparatus of claim 14, wherein the second resistance is a resistance.

Claim 18

The apparatus of claim 13, wherein the first impedance is a resistance of approximately one megohm, and the second impedance is a resistance of approximately 10 K ohms.

Claim 19

The apparatus of claim 15, wherein the second voltage is a ground potential.

Claim 20

The apparatus of claim 17, wherein the first voltage is positive.

Claim 23

The method of claim 19, wherein the applying step includes providing an impedance to couple the voltage level to the signal line.

Claim 24

The method of claim 20, wherein the impedance comprises a first resistance to couple the voltage level to the signal line.

Claim 25

The method of claim 21, wherein the impedance includes a second resistance.

Claim 26

The method of claim 22, wherein the first resistance is coupled between a supply voltage and the signal line, and the second resistance is coupled between the signal line and a ground potential.

Claim 27

The method of claim 23, wherein the supply voltage is a positive voltage.

Claim 28

Apparatus for using a signal line to communicate a signal from a first component connected to a second electronic component and to provide an indication that the second component is not connected to receive the signal, the apparatus comprising: a driver element having an output coupled to the signal line, the driver element operating in a first mode to communicate the signal from the output to the signal line and in a second mode in which the output is in a high impedance state; a receiver coupled to the signal line to provide the indication when a predetermined voltage level is present on the signal line; and a first impedance coupled to a first voltage and to the signal line to apply the predetermined voltage level to the signal line when the output is placed in the high impedance state, the first impedance being coupled between the first voltage and the signal line, and a second impedance coupled between the signal line and a second voltage that is less in magnitude than the first voltage.

Claim 29

Apparatus for using a signal line to communicate a signal from a first component connected to a second electronic component and to provide an indication that the second component is not connected to receive the signal, the apparatus comprising: a driver element having an output coupled to the signal line, the driver element operating in a first mode to communicate the signal from the output to the signal line and in a second mode in which the output is in a high impedance state; a receiver coupled to the signal line to provide the indication when a predetermined voltage level is present on the signal line; and a first impedance coupled to a first voltage and to the signal line to apply the predetermined voltage level to the signal line when the output is placed in the high impedance state, the first impedance being coupled between the first voltage and the signal line, and a second impedance coupled between the signal line and a second voltage that is less in magnitude than the first voltage.

Claim 30

The apparatus of claim 25, wherein the first voltage is positive.

Claim 31

The apparatus of claim 26, wherein the second voltage is a ground potential.

Claim 32

The apparatus of claim 1, wherein the one electronic unit includes the receiver.

Claim 33

Apparatus for determining that a first component is communicatively coupled by a signal line to a second component, comprising: a driver included with the first component and having an output coupled to the signal line to communicate an operating signal thereon, the driver element operating to have the output selectively placed in a high impedance state; a receiver included with the first component and coupled to the signal line to provide a sense signal when a predetermined voltage level is present one the signal line; and an impedance coupled to a first voltage and to the signal line to provide the predetermined voltage level to the signal line when the driver element output is placed in a high impedance state and the second component is not communicatively coupled to the signal line.

Claim 34

Apparatus for determining that a first component is communicatively coupled by a signal line to a second component, comprising: a driver included with the first component and having an output coupled to the signal line to communicate an operating signal thereon, the driver element operating to have the output selectively placed in a high impedance state; a receiver included with the first component and coupled to the signal line to provide a sense signal when a predetermined voltage level is present one the signal line; and an impedance coupled to a first voltage and to the signal line to provide the predetermined voltage level to the signal line when the driver element output is placed in a high impedance state and the second component is not communicatively coupled to the signal line.

Claim 35

The apparatus of claim 29, wherein the impedance includes a first impedance coupled to the first voltage, and a second impedance in series connection with the first impedance coupled to a second voltage that is less in magnitude than the first voltage.

Claim 36

The apparatus of claim 29, wherein the predetermined voltage is positive.

Claim 37

The apparatus of claim 30, wherein the first voltage is positive.

Claim 38

The apparatus of claim 30, wherein the second voltage is approximately a ground potential.

Claim 41

Apparatus for using a signal line to communicate an operating signal from one electronic unit to another electronic unit and to detect the another electronic unit is communicatively connected to the signal line, the apparatus comprising: the one electronic unit including a driver element having an output that communicates the operating signal to the signal line, the driver element operating to have the output placed in a high impedance state; an impedance coupled to the signal line and to a voltage to apply a first voltage level to the signal line indicative of communicative connection of the another electronic unit to the signal line and to apply a second voltage level indicative of no communicative connection of the second electronic unit to the signal line when the driver element output is placed in the high impedance state; and means for sensing the first or second voltage levels.

Claim 42

Apparatus for using a signal line to communicate an operating signal from one electronic unit to another electronic unit and to detect the another electronic unit is communicatively connected to the signal line, the apparatus comprising: the one electronic unit including a driver element having an output that communicates the operating signal to the signal line, the driver element operating to have the output placed in a high impedance state; an impedance coupled to the signal line and to a voltage to apply a first voltage level to the signal line indicative of communicative connection of the another electronic unit to the signal line and to apply a second voltage level indicative of no communicative connection of the second electronic unit to the signal line when the driver element output is placed in the high impedance state; and means for sensing the first or second voltage levels.

Claim 43

The apparatus of claim 35, wherein the first electronic component includes the means for sensing.

Claim 44

The apparatus of claim 35, wherein the voltage is positive.

Claim 45

Apparatus for using a signal line that communicates an operating signal from one electronic unit to another electronic unit to also detect the connection of the another electronic unit to the signal line, comprising: a driver element, forming a part of the one electronic unit, and having an output that communicates the operating signal to the signal line, the driver element operating to have the output placed in a high impedance state; a buffer element coupled to the signal line to provide a sense signal indicative of connection of the another electronic unit by presence of a predetermined voltage level on the signal line; and an impedance coupled to a voltage to apply the predetermined voltage level to the signal line when the driver element output is placed in the high impedance state, the impedance including a first impedance element coupled between the voltage and the signal line and a second impedance element that couples the signal line to a voltage potential.

Claim 46

Apparatus for using a signal line that communicates an operating signal from one electronic unit to another electronic unit to also detect the connection of the another electronic unit to the signal line, comprising: a driver element, forming a part of the one electronic unit, and having an output that communicates the operating signal to the signal line, the driver element operating to have the output placed in a high impedance state; a buffer element coupled to the signal line to provide a sense signal indicative of connection of the another electronic unit by presence of a predetermined voltage level on the signal line; and an impedance coupled to a voltage to apply the predetermined voltage level to the signal line when the driver element output is placed in the high impedance state, the impedance including a first impedance element coupled between the voltage and the signal line and a second impedance element that couples the signal line to a voltage potential.

Claim 49

Apparatus for determining that a first component is communicatively coupled by a signal line to a second component, comprising: a driver included with the first component and having an output coupled to the signal line to communicate an operating signal thereon, the driver element operating to have the output selectively placed in a high impedance state; a buffer included with the first component and coupled to the signal line to provide a sense signal when a predetermined voltage level is present on the signal line; and an impedance coupled to a first voltage and to the signal line to provide the predetermined voltage level to the signal line when the driver element output is placed in a high impedance state and the second component is not communicatively coupled to the signal line; wherein the impedance includes a first impedance coupled to the first voltage, and a second impedance in series connection with the first impedance coupled to a second voltage that is less in magnitude than the first voltage.

Claim 50

Apparatus for determining that a first component is communicatively coupled by a signal line to a second component, comprising: a driver included with the first component and having an output coupled to the signal line to communicate an operating signal thereon, the driver element operating to have the output selectively placed in a high impedance state; a buffer included with the first component and coupled to the signal line to provide a sense signal when a predetermined voltage level is present on the signal line; and an impedance coupled to a first voltage and to the signal line to provide the predetermined voltage level to the signal line when the driver element output is placed in a high impedance state and the second component is not communicatively coupled to the signal line; wherein the impedance includes a first impedance coupled to the first voltage, and a second impedance in series connection with the first impedance coupled to a second voltage that is less in magnitude than the first voltage.