Abstract:
An apparatus and method for enabling remotely controlling power status of a remote device. The apparatus monitors information signals being transmitted to the remote device and from such information, determines whether to alter the power status of the remote device. The apparatus may include an uninterruptable power source to enable such remote control during an interrupt of main power to the apparatus.

Description:
This is a Continuation Application of application Ser. No. 08/183,196, filed Jan. 14, 1994 now abandened. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method for managing power conditions of a computer system. More specifically, the present invention relates to an apparatus coupled to a communication line to remotely control a power status of a remote device and a method for performing such remote power management. 
     2. Background of the Field 
     Throughout the last decade, business have realized that a networked system incorporating a desired number of workstations and at least one server is generally more cost effective than purchasing the desired number of stand-alone computers, each of which having a large internal memory. The networked system is typically a number of servers (e.g., computers, workstations, etc.) coupled through a communication line, such as a dedicated RS 232 line, to at least one server node. Hereinafter, a “server node” refers to any device which typically operates in cooperation with a server, including but not limited to a host server. 
     One problem associated with networked systems employing server nodes being large in size is that the server nodes are typically stored in remote computer rooms within the same building or perhaps even miles away, causing support difficulties. Thus, in order to control power consumption of the server nodes and to reboot server nodes if any of them have “frozen”, support personnel had to physically “power-off” or “power-on” these server nodes. This support technique was not cost-effective because many support personnel are needed in order to support a multiple building corporation having tens or hundreds of server nodes. Moreover, it is time consuming for the support personnel to physically power-off or power-on the server nodes. 
     Recently, a company designed a conventional power switch (hereinafter referred to as the “IPC 3100”) as shown in FIG.  1 . The IPC 3100  1  is designed to remotely supply 110 volts of AC power (“110 VAC”) through each of its four power outlets  2   a - 2   d  for use by a single host server as illustrated or up to four host servers. The IPC 3100  1  is powered by a conventional 110 VAC power supply  3  which is connected to the IPC 3100  1  through an AC power connection cord  4 . The IPC 3100  1  transfers the 110 VAC to the host server  5  through at most four corresponding power connection signal lines of which only three lines  6   b - 6   d  are shown. Therefore, the IPC 3100  1  is incapable of supporting host servers having power requirements different than 110 VAC, such as 220 VAC and non-domestic voltage levels. 
     In a conventional networking scheme, a first serial port  8  of a terminal (i.e., console) server  7  is coupled to a first serial port  9  of the host server  5  through a first serial communication line  10 , usually a RS 232 signal line. To install the IPC 3100  1  within the conventional networking scheme, new hardware is typically needed because the console server  7  requires a second serial port  11  for electrically connecting the IPC 3100  1  to the console server  7 . Therefore, installation of the IPC 3100  1  is typically extremely difficult and costly to perform because the console server  7  normally does not have the unused second serial port  11 . Even if the console server  7  has the unused second serial port  11 , installing the IPC  3100   1  would require the serial port  11  of the console server  7  to be reprogrammed. 
     The next step for implementing the IPC 3100  1  is to install a second dedicated serial communication line  12  in order to electrically couple the console server  7  to the IPC 3100  1 . 
     A final step for implementing the IPC 3100  1  is that support personnel must re-route each of the power connection signal lines  6   b - 6   d  which are directly coupled to the host server  5 . For companies having tens or hundreds of console and host servers, purchasing, implementing and re-routing the above-indicated signal lines can be a costly and time consuming process. 
     As briefly alluded to above, there are many disadvantages associated with the IPC 3100. A first disadvantage is that the IPC 3100 is extremely difficult to install, and in some case, impossible to install. A second disadvantage is that the IPC 3100 is expensive to install. As discussed above, the IPC 3100 does not fully utilize existing hardware, but rather, requires additional hardware to be installed, if at all possible. As a result, implementing the IPC 3100 is costly in view of additional material costs (cables, serial ports, etc.) and labor costs associated with installation, especially for companies having tens or hundreds of host servers. 
     A third disadvantage is that the IPC 3100 has no power outage management features. The IPC 3100  1  is solely AC powered. In the event of a sudden power-outage, there would be no remote access to the host servers because no AC power would be available to the IPC 3100. The lack of remote access would require support personnel to physically power-off the host servers until power was restored. This lack of remote access during power outages subjects the host-server to severe damage if it experiences an electric spike. Although support personnel may be able to quickly reach a few host servers to protect them from potential damage, it is highly doubtful that the support personnel would be able to power-off every host server in the event that the electric spike occurs. 
     Another disadvantage is that the IPC 3100 can not be used to remotely control computers that do not require power other than 110 VAC. Therefore, the IPC 3100 does not support a wide range of computer systems. 
     Another disadvantage is associated with the IPC 3100 is that it functions at a slow baud rate of 2400 bps. Therefore, for a majority of machines capable of operating at a greater baud rates, the IPC 3100 would require limitations in the networked system&#39;s communication speed. 
     Furthermore, the IPC 3100 fails to provide a feature to effectively prevent users from remotely altering the power status of the host server while the host server is being repaired. Of course, this could be done by unplugging the second dedicated serial communication line, but then, there poses risks of damaging the serial port, the dedicated serial communication line itself as well as exposing the support personnel to difficulties in re-connecting the second dedicated serial communication line. 
     SUMMARY OF THE INVENTION 
     In light of the foregoing, it will be apparent from the below description that the present invention overcomes the above-mentioned disadvantages and limitations associated with the conventional prior art power switches by remotely managing power to a remote device by tapping a pre-existing communication line coupling a remote device to another device without additional reconfiguration of a networked system. 
     The apparatus comprises a serial port circuit which receives information from and transmits information onto the first serial communication line in order to monitor communication activity directed toward the remote device. The apparatus further comprises a processing unit which determines whether a request, such as a predetermined sequence, has been transmitted to the remote device. If so, the processing unit alters the power status of the remote device by generating and transmitting a control signal to a switch control circuit. The switch control circuit will, in turn, activate or deactivate the remote device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects of the present invention will be described with respect to the following figures in which. 
     FIG. 1 is a block diagram of a conventional prior art remote power controller, namely a IPC 3100, operating as a power switch for a host server. 
     FIG. 2 is a block diagram of a networked system incorporating the present invention coupled to a communication line enabling communication between a server and a server node. 
     FIG. 3 is a more detailed circuit block diagram of one embodiment of the present invention. 
     FIG. 4 is a timing diagram of the operation of a relay switch in the embodiment illustrated in FIG. 3 based on a specific output of a processing unit. 
     FIG. 5 is a detailed circuit block diagram of a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A remote power controller and method are described which can be used to remotely control power application to a host computer. In the following description, numerous specific details are set forth, such as the specific circuit components of the present invention. It is apparent, however, to one skilled in the art that the present invention may be practiced without incorporating the specific circuit components. Moreover, a specific example has been created for the sole purpose of illustrating the operations of the present invention. This specific example lends itself to only explaining the operation of the present invention and should not be construed in any way as a limitation on the scope of the present invention. 
     FIG. 2 illustrates one embodiment of the remote power controller employed within a conventional networked computer system. The remote power controller  20  is coupled to a main communication signal line  21  typically pre-existing in the conventional networked computer system. The main communication signal line  21  couples a first and second devices together, namely, a server  22  and a server node  23 . However, such devices could be any pair of devices wherein the server  22  has remote access to the server node  23  having a power connector  29 , such as a modem and a host server, two host servers, a computer and a host server and the like. 
     The remote power controller  20  is coupled to the main communication line  21  through a connector  24  and a second communication signal line  25  having a configuration identical to the main communication signal line  21 . 
     The connector  24  and second communication signal line  25  enable an information signal generated by the server  22  to be received by the server node  23  and the remote power controller  20 . Although illustrated as external to the remote power controller  20 , the connector  24  and second communication signal line  25  could be incorporated within the power controller  20 , eliminating a need for the second communication line  25  itself. 
     In FIG. 2, the second communication line  25 , which has an arbitrary length but less than the second dedicated serial communication line  12  shown in FIG. 1, is coupled to serial port circuitry  26  which receives information placed on the main communication signal line  21 , converts the information from RS 232 voltage levels to TTL voltage levels if the main communication line  21  is a RS 232 line, and drives the information into a processing unit  27 . Upon receipt of information formulating a predetermined sequence of character values, the processing unit  27  will generate a control signal to a switch control circuit  28  to activate or deactivate a power connector  29  of the server node  23  in order to power-on or power-off the server node. Alternatively, of course, the server node  23  could be powered-on/powered-off by deactivating/activating the power connector  29  if the configuration of the power controller so dictates. 
     In the embodiments illustrated in FIGS. 3 and 5, the power connector  29  comprises a multi-pin interface being an industry standard utilized by many computer technology manufacturers, including Sun Microsystems, Inc. of Mountain View, California. This interface requiring three wires, wherein a maintained closure between pins  1  (top) and  3  (bottom) of the power connector  29  will remotely power-on the server node  23  and a maintained opening of these pins will remotely power-off the server node  23 . Pins  1  and  2  have open circuit voltages of +12 VDC and pin  3  is chassis ground. However, it is contemplated that any power controller could be used to perform the same function of turning off or on the server node  23  upon detection of a control signal. 
     The processing unit  27  is further coupled to an uninterruptable 5-volt power circuit  30  to provide the processing unit  27  with an alternate power supply in case its main power supply is disconnected. The processing unit  27  typically obtains its main power from a keyboard port or an AC adapter on the server node  23 . 
     In the above-illustrated embodiment, the power controller  20  is able to support server nodes requiring any preselected amount of voltage power (e.g., 220 volts) since the power controller  20  directly turns off the power connector of the server node itself. In contrast, the conventional prior art power switch directly provides 110 VAC to the server node  23 . In addition, the remote power controller  20  operates at a baud rate of 9600 bps, supporting faster communication systems. 
     As previously mentioned, the operations of the present invention may best be described through a simple example. This example merely assists in explaining the operation of the present invention, and should in no way be construed as a limitation on the scope of the present invention. Suppose the remote power controller  20  is designed so that it powers-off the server node  23  upon detection of a “control GOFF” (i.e., a sequence of &lt;Cntl G&gt; &lt;Cntl O&gt; &lt;Cntl F&gt; &lt;Cntl F&gt;) on the main communication signal line  21  and powers-on the server node  23  upon detection of a “control GON”. The remote power controller  20  is coupled to he main communication signal line  21  through second communication signal line  25  or any similar material in order to monitor the main communication signal line  21 . 
     Upon detection of the “control GOFF” sequence, the processing unit  27  causes the switch control circuit  28  to generate a control signal into the power connector  29  so that the server node  23  powers-off. Similarly, the detection of a “control GON” will cause the remote power controller  20  to power-on the server node  23 . In case of a “control GON” or “control GOFF” is detected when the server node  23  is powered-on or powered-off respectfully, no change in power status will occur. 
     Referring now to FIG. 3, a detailed circuit diagram of the present invention is illustrated. However, it is contemplated that the present invention could be designed with other comparable chips. As shown in FIG. 3, the present invention comprises the connector  24 , serial port circuitry  26 , processing unit  27 , switch control circuit  28  and the uninterruptable power circuitry  30 . The connector  24 , preferably an industry standard RJ-11 or DB-25F connector, is coupled to the main communication signal line  21  and the serial port circuitry  26 . The coupling between the connector  24  and the serial port circuitry  26  includes a pair of serial port signal receive and transmit lines  41  and  42  to allow the serial port circuitry  26  to receive data from and transmit data onto the main communication signal line  21 . 
     The serial port circuitry  26  comprises a serial driver chip  40  to transmit the data signals to a microprocessor  45 . The serial driver chip  40  in this embodiment is a RS 232 driver chip, namely a 20-pin MAX233 manufactured by Maxim Corporation, in view of the fact that typical conventional networks employ RS 232 communication lines. It is contemplated that any other appropriate serial driver chip could be used to provide the same functionality. 
     The driver chip  40  is configured in a manner illustrated in FIG. 3 so that external capacitors are not required to increase voltage to ±10 volts, namely the RS 232 voltage level, making the remote power controller  20  easier to construct. Although the embodiment illustrates two separate signal lines  41  and  42  to receive and transmit data, respectively, only one signal line is actually required for unidirectional communication since the serial port transmit signal line  42  is only used for sending information regarding the communications to an operator. 
     The serial port receive signal line  41  is further coupled to a negative voltage regulator  47  which provides negative voltage to prevent unintended break sequences. For certain older server nodes, negative voltage reapplied to the serial port receive signal line  41  after a negative voltage loss for a duration of at least one second, will cause the server node to abort its currently running program. This type of abort is not a genuine break sequence since it is not intended. By the negative voltage regulator  47  holding a negative five volts on the serial port receive signal line  41 , the serial port receive line  41  will remain at a negative voltage, preventing unintended break sequences while allowing normal serial communication to still occur. 
     The driver chip  40  includes a pair of TTL level transmit and receive signal lines  43  and  44  coupled to the microprocessor  45  and a power conversion signal line  46  used to convert a positive five volt voltage into an appropriate negative voltage on pin  5  of the serial driver  40 . This pair of transmit and receive signal lines  43  and  44  provides the microprocessor  45  necessary information, such as character values, from which it can determine whether to power-off or power-on the server node  23 . 
     The microprocessor  45  is preferably, but not required to be, a low power microprocessor such as Intel ™ 87C51, a Dallas Semiconductor DS5000 and the like. A low power consumption microprocessor is preferred, but not required, since the microprocessor  45  needs to operate under battery power during a power outage. 
     As shown in FIG. 3, the Intel ™ 87C51 is featured as the microprocessor  45  to illustration one of many possible embodiments. In the Intel ™ 87C51, pin  40  and pin  31  of the microprocessor  45  are tied together and powered by 5 volts. Pin  20  is a ground pin which is connected to ground while pin  9  is a reset pin which is coupled to a 5 volt supply using capacitor  48  to provide a power-on reset. Pins  18  and  19  are coupled to an oscillating crystal  49  for clocking the microprocessor  45 . The microprocessor  45  can operate with clock frequency ranges between 3 and 12 MHz, but for the preferred embodiment, the crystal  49  has a frequency of approximately 11 MHz. Capacitors  50  and  51  are also coupled to pins  18  and  19  to provide oscillation of the crystal  49 . 
     Port pin  1  of the microprocessor  45  is coupled to an inverter  53  and a relay  55  in series. When the port pin  1  is “high,” the power connector  29  of the server node  23  is powered-on because there exists a coupling between a relay switch  57  and a power-on signal line  58 . However, when port pin  1  is “low”, the relay switch  57  is coupled to the power-off signal line  59 . Port pin  2 , on the other hand, is coupled to a diagnostic LED  54  that will be on/off when the server node  23  is powered-on/powered-off, respectively. The LED  54  is just a visual aid to help identify the power status of the server node  23  or to identify problems with the remote power controller  20 . 
     In FIG. 3, the uninterruptable power supply circuitry  30  includes a battery source  60  coupled indirectly to an AC-to-DC converter  61 . The remote power controller  20  is coupled to any port, adapter and the like providing five volts, including but not limited to, an AC adapter or a keyboard port  62  on the server node  23  as shown in FIG.  3 . The keyboard port  62  is coupled to the AC-to-DC converter  61  through two leads  63  and  64 , wherein the first lead  63  is coupled to the battery source  60 . The battery source  60  comprises a nickel cadmium cell(s) (“NiCad”) battery  65  coupled between ground  66  and a Schottky diode  67  having a 680 Ω resister  68  in parallel with the Schottky diode  67 . The resistor  68  will keep the NiCad battery  65 , or the rechargeable battery of the user&#39;s choice, charged (i.e., trickle charged). When the five volts is provided by the keyboard port  62 , no power is needed from the NiCad battery  65 . Instead, the battery  65  is trickle charged so that a small amount of current is used to keep the batteries fully charged. 
     The AC-to-DC converter  61  has dual inputs  69  and  70  and dual outputs  71  and  72 . A first output  71  is coupled to the microprocessor  45  in which the first output indicates whether the battery source  60  is falling below a predetermined level so as to allow the microprocessor  45  to perform certain “housekeeping” functions in order to prepare the microprocessor  45  for a cessation of power. A second output  72  of the AC-to-DC converter  61  is coupled to a five-volt power bus  73  which provides necessary voltage to drive the circuitry throughout in the remote power controller  20 . Coupled between the second output  72  and the power bus  73  is a maintenance lock out switch  74  which, when closed as shown, enables power to be supplied to the serial port circuitry  26 , processing unit  27  and the switch control circuit  28  within the remote power controller  20 . However, if the maintenance lockout switch  74  is disconnected, the power in each of the circuits would be disconnected so that remote control of the power status of the host server would be inoperative. 
     Referring to FIGS. 3 and 4, the output of the relays is disclosed in a time diagram. By default, the port pin  1  of the microprocessor  45  is active (“high”) on a power-on. This drives the inverter  53  within an inverter chip  52  low so that no voltage is present on a coil  56  of the relay  55 . Thus, a relay switch  57  is normally closed so that in the absence of voltage, the server node  23  remains powered-on. When a power-off command is issued, the port pin  1  goes low, which drives the inverter  53  high. As a result, the coil  56  is energized to drive the relay switch  57  to its open position, as illustrated by ghost lines, coupling the relay switch  57  with the power-off signal line  59 . In the open position, the host server is powered-off. Conversely, when the power-on command is issued, the port pin  1  goes high, the inverter  53  goes low, the relay switch  57  is closed coupling itself to the power-on signal line  58  to apply power to the server node  23 . It is contemplated that the switching mechanism could be designed with a single control signal line in combination with certain conventional control logic being coupled to the power connector  29 . 
     Referring to FIG. 5, a second embodiment of the present invention is illustrated. In this embodiment, a RS 232 driver  100  is coupled to the connector  101  of the main communication signal line similar to the embodiment shown in FIG. 3 through a pair of receiving and transmitting signal lines  102  and  103 . Unlike the RS 232 driver  40  such as, for example, the MAX233 driver in FIG. 3, the RS 232 driver  100  shown in FIG. 5 requires external capacitors  104   a - 104   c  for use by a charge pump internal to the MAX233 driver chip to increase the voltage from five volts to a requisite ± 10 volts for RS 232 application. The RS 232 driver  100  is coupled to microprocessor  107  through a pair of transmitting and receiving output signal lines  105  and  106 . 
     The microprocessor  107  illustrated in FIG. 5, preferably an Intel ™ 8051 microprocessor, is different from the Intel ™ 87C51 microprocessor illustrated in FIG. 3 in that the Intel ™ 8051 (hereafter referred to as “the microprocessor  107 ”) requires an external EPROM  108  for programming purposes. The combination address and data lines  120 - 127  of the microprocessor  107  are coupled to an eight bit latch  109  which simply acts as an intermediate chip in order to store the address information for use during the data cycle. The eight bit latch  109  is commonly used to store such data because the address lines are also used as data lines during subsequent clock cycles. This address information is stored for use by the memory chip during these subsequent clock cycles. The eight bit latch  109  enables one to store address information so that it can be used subsequent to the current clock cycle. This allows the external EPROM  108  to decode the address and put the data on the data lines when a signal line from pin  40  of the microprocessor  107  is activated. 
     As in the previous embodiment the microprocessor  107  is coupled through dual signal lines  108  and  109  to a pair of inverters  110  and  111  such that a second signal line  109  is used to activate or deactivate an LED  112  in order to indicate power status or problems with the system, while first output  108  is used to power on or off the server node. 
     Power is provided to the above-identified circuits through an AC adapter  113 . Here, in this embodiment, there is no implementation of an uninterruptable voltage supply; rather, the voltage is obtained by the AC adapter  113  which is coupled to a voltage regulator  114  used to alter the twelve volts inputted therein to a five volt output. The voltage regulator  114  is coupled to a micro-controller power bus  115  which provides power to the microprocessor  107 , the eight bit latch  109 , the EPROM  108  and the RS 232 driver  100 . Interposed between the output of the voltage regulator  114  and the micro-controller power bus is a maintenance lockout switch  116  which disables power to the above-identified circuitry when disconnecting lines  117  and  118 . As a result, remote access to the server node to vary the power status is discontinued. 
     The present invention described herein may be designed in many different methods and using many different components. For example, it is contemplated that a receiver could be employed to detect radio transmissions between a first and a second device for power controlling reasons. While the present invention has been described in terms of various embodiments, other embodiments may come to mind to those skilled in the art without departing from the spirit and scope of the present invention. The invention should, therefore, be measured in terms of the claims which follow.