System and method for detecting a device requiring power

Abstract

A system and technique for detecting a device that requires power is implemented with a power detection station. The power detection system includes a detector having an output and a return which are coupled together by the device when the device requires power. The detector includes a word generator for generating test pulses for transmission to the device via the detector output, and a comparator for comparing the detector output with the detector return. The power detection station has a wide variety of applications, including by way of example, a switch or hub.

1 . A power detection system, comprising: 
 a detector having an output and a return; and    a device to selectively couple the detector output to the detector return when the device requires power.    
   
   
       2 . The power detection system of  claim 1  wherein the detector output comprises a signal having a first pulse with a first pulse width and a second pulse with a second pulse width different from the first pulse width, said filter passing the first pulse and attenuating the second pulse.  
   
   
       3 . The power detection system of  claim 2  wherein the second pulse width is programmable.  
   
   
       4 . The power detection system of  claim 2  wherein the detector determines that the device requires power when the detector return comprises the first pulse but not the second pulse.  
   
   
       5 . The power detection system of  claim 4  further comprising a power source selectively coupled to the device when the detector determines that the device requires power.  
   
   
       6 . The power detection system of  claim 1  wherein the detector output comprises a signal, and the detector determines that the device requires power when the detector return comprises the signal.  
   
   
       7 . The power detection system of  claim 6  wherein the detector determines that the device requires power only if the detector return comprises the signal within a predetermined time window.  
   
   
       8 . The power detection system of  claim 7  further comprising a power source selectively coupled to the device when the detector determines that the device requires power.  
   
   
       9 . The power detection system of  claim 1  wherein the detector output includes a pseudo random word comprising a plurality of pulses.  
   
   
       10 . The power detection system of  claim 1  wherein the detector output comprises a identifier comprising a plurality of pulses.  
   
   
       11 . The power detection system of  claim 1  further comprising a power source selectively coupled to the device.  
   
   
       12 . The power detection system of  claim 1  wherein the device comprises an IP telephone.  
   
   
       13 . A detecting station having an input and a return, comprising: 
 a word generator couplets to the detecting station output; and    a comparator to compare the detecting station output with the detecting station return.    
   
   
       14 . The detecting station of  claim 13  wherein the word generator comprises a free running timer.  
   
   
       15 . The detecting station of  claim 13  further comprising a controller having an address, and wherein the word generator comprises an output having the controller address.  
   
   
       16 . The detecting station of  claim 13  further comprising a pulse shaping device coupled between the word generator and the detecting station output.  
   
   
       17 . The detecting station of  claim 16  wherein the pulse shaping device is programmable, the detecting station further comprising a controller to program the pulse shaping device.  
   
   
       18 . The detecting station of  claim 17  further comprising a power source, and wherein the controller programs the pulse shaping device to output a first pulse having a first pulse width and a second pulse having a second pulse width different from the first pulse width, the controller enabling the power source when the comparator detects the first pulse but not the second pulse.  
   
   
       19 . The detecting station of  claim 13  further comprising a power source, and a controller to enable the power source in response to a comparator output.  
   
   
       20 . The detecting station of  claim 19  further comprising a register coupled between the word generator and the detecting station output, the register latching a word generator output in response to a trigger from the controller, and a timer enabled by the trigger for a predetermined time thereafter, the power source being enabled by the controller in response to the comparator output only while the timer is enabled.  
   
   
       21 . A method for detecting a device requiring power, comprising: 
 transmitting a pulse to the device;    receiving the pulse from the device; and    detecting whether the device requires power in response to the received pulse.    
   
   
       22 . The method of  claim 21  wherein the power requirement detection comprises applying power to the device.  
   
   
       23 . The method of  claim 21  wherein the pulse transmission comprises transmitting a pseudo random word comprising a plurality of pulses.  
   
   
       24 . The method of  claim 21  wherein the pulse transmission comprises transmitting a identifier comprising a plurality of pulses.  
   
   
       25 . The method of  claim 21  wherein the transmitted pulse has a pulse width, the method further comprising transmitting another pulse having a different pulse width to the device.  
   
   
       26 . The method of  claim 25  further comprising programming the second pulse width.  
   
   
       27 . The method of  claim 25  wherein the power requirement detection comprises applying power to the device when the received pulse comprises the transmitted pulse but not said another transmitted pulse.  
   
   
       28 . The method of  claim 21  wherein the power requirement detection comprises applying power to the device when the received pulse comprises the transmitted pulse.  
   
   
       29 . The method of  claim 28  wherein the power requirement detection comprises applying power to the device when the received pulse comprises the transmitted pulse within a predetermined time after the transmitted pulse is transmitted to the device.  
   
   
       30 . The method of  claim 21  wherein the device comprises an IP telephone.  
   
   
       31 . A transmission system, comprising: 
 a transmission line interface having at least one port;    a two-way transmission line coupled to one of the ports; and    a device coupled to the two-way transmission line, the device selectively coupling the two-way transmission line together when the device requires power.    
   
   
       32 . The transmission system of  claim 31  wherein the transmission line interface outputs first and second pulses to the device through the two-way transmission line, each of the pulses having a pulse width different from one another.  
   
   
       33 . The transmission system of  claim 32  wherein the second pulse width is programmable.  
   
   
       34 . The transmission system of  claim 32  wherein the transmission line interface determines that the device requires power when the transmission line interface detects the first pulse from the two-way transmission line but not the second pulse.  
   
   
       35 . The transmission system of  claim 34  wherein the transmission line interface further comprises a power source selectively coupled to the device through the two-way transmission line when the transmission line interface determines that the device requires power.  
   
   
       36 . The transmission system of  claim 31  wherein the transmission line interface outputs a signal to the device through the two-way transmission line, and the transmission line interface determines that the device requires power when the transmission line interface detects the signal from the device through the two-way transmission line.  
   
   
       37 . The transmission system of  claim 36  wherein transmission line interface determines that the device requires power only if the transmission line interface detects the signal from the device through the two-way transmission line within a predetermined time after the transmission line interface outputs the signal.  
   
   
       38 . The transmission system of  claim 37  wherein the transmission line interface further comprises a power source selectively coupled to the device through the two-way transmission fine when the transmission line interface determines that the device requires power.  
   
   
       39 . The transmission system of  claim 31  wherein. the transmission line interface outputs a pseudo random word comprising a plurality of pulses.  
   
   
       40 . The transmission system of  claim 31  wherein the transmission line interface outputs a identifier comprising a plurality of pulses.  
   
   
       41 . The transmission system of  claim 31  wherein the transmission line interface comprises a power source selectively coupled to the device through the two-way transmission line.  
   
   
       42 . The transmission system of  claim 31  wherein the device comprises an IP telephone.  
   
   
       43 . The transmission system of  claim 31  further comprising a second device not requiring power.  
   
   
       44 . The transmission system of  claim 43  wherein the device comprises an IP telephone and the second device comprises a computer.  
   
   
       45 . The transmission system of  claim 43  wherein the transmission line interface comprises a power source selectively coupled to the device through the two-way transmission line.  
   
   
       46 . The transmission system of  claim 45  wherein the transmission line interface provides two-way communication between the device and the second device when the power source is selectively coupled to the device.  
   
   
       47 . The transmission system of  claim 31  wherein the transmission line interface comprises a switch.  
   
   
       48 . A detector having an output and a return, comprising: 
 a word generator coupled to the detector output; and    a comparator to compare the detector output with the detector return.    
   
   
       49 . The detector of  claim 48  wherein the word generator comprises a free running timer.  
   
   
       50 . The detector of  claim 48  further comprising a pulse shaping device coupled between the word generator and the detector output.  
   
   
       51 . The detector of  claim 50  wherein the pulse shaping device is programmable.  
   
   
       52 . The detector of  claim 51  wherein the pulse shaping device is programmed to output a first pulse having a first pulse width and a second pulse having a second pulse width different from the first pulse width.  
   
   
       53 . The detector of  claim 48  further comprising a register coupled between the word generator and the detector output, the register latching a word generator output in response to a trigger, and a timer enabled by such trigger for a predetermined time thereafter, the comparator being enabled only while the timer is enabled.