Patent Description:
One example of the present disclosure as recited in claim <NUM> is a load control system for access control, comprising: a power supply; a load controller configured to be coupled to a load, the load controller configured to receive a first power having a first current level from the power supply, and to communicate information regarding the load by executing an enumeration process using a plurality of resistors, in which each resistor is caused to output a pre-defined code, and by connecting each of the plurality of resistors to the power supply to cause the plurality of resistors to draw pre-defined amounts of current from the power supply and output a plurality of pre-defined codes; and a supply controller that is configured to receive the plurality of pre-defined codes, evaluate an output condition based on matching the plurality of pre-defined codes to a plurality of corresponding supply codes, and cause the power supply to output a second power having a second current level greater than the first level responsive to the plurality of pre-defined codes satisfying the output condition.

Another example of the present disclosure as recited in claim <NUM> is a method for access control, comprising:
setting, by at least one of a supply controller and a power supply, a current limit of the power supply to a first value; connecting, by the supply controller, the power supply to a load controller; generating, by the load controller, a plurality of pre-defined codes using a first power having a first current level less than or equal to the first value of the current limit, wherein the pre-defined codes are generated by the load controller executing an enumeration process using a plurality of resistors, by connecting each of the plurality of resistors to the power supply to cause the plurality of resistors to draw pre-defined amounts of current from the power supply and output the plurality of pre-defined codes; receiving, at the supply controller, the plurality of pre-defined codes; evaluating, by the supply controller, an output condition based on matching the plurality of pre-defined codes to a plurality of corresponding supply codes; increasing, by the supply controller, the current limit to a second value greater than the first value responsive to the plurality of pre-defined codes satisfying the output condition; and connecting, by the supply controller, the load to the power supply responsive to the plurality of pre-defined codes satisfying the output condition.

Preferred embodiments are defined in dependent claims.

Before turning to the figures, which illustrate certain embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

The present disclosure relates generally to the field of access control systems, and more particularly to systems and methods of lock and powered load enumeration and secure activation. Referring generally to the figures, an access control system can control electronic locks and other loads by delivering power from a power supply to the load. In existing systems, the locks and loads may be directly controlled from the power supply source. This can result in a lack of over-current protection to prevent brown-outs; a lack of functionality regarding planned currently delivery or dynamic allocation; uncertainty as to whether the load connected is of a correct type or manufacturer; and/or the load being unsafe to connect and/or not functioning properly. For example, access control systems may have generic or universal connections that can allow an installer to connect a wide variety of locks or loads to the access control system, even if the connected lock or load may not be able to function properly with the access control system, including to draw an appropriate current from the access control system when activated.

The present solution can enable access control systems to more effectively manage power delivery to locks and loads, including to budget power delivery and power supply (e.g., battery) usage based on identifying specific parameters of the lock and/or load connected to the access control system. In some embodiments, the present solution does not increase the amount or complexity of wiring, and can be retrofitted into already installed systems. The present solution can enable access control systems to verify origin and type of locks or loads to prevent future over-current situations, and to verify that the equipment in use is authentic. In some embodiments, the present solution enables a very low level of current to power a small circuit in the load; subsequently, a series of codes can be signaled back from the load to the power supply, which can be verified to determine whether to activate a higher level of power supply and current limit to connect the load to the full supply. By implementing various such features, the present solution can enable over-current protection to prevent brown-outs, plan current delivery and/or make dynamic current allocation to the loads connection (e.g., battery re-charging can be accelerated by using any spare current, or restricted to maintain service), reduce or eliminate uncertainty regarding the type, manufacturer, or other parameters of the load, and effectively report errors if the load is unsafe or otherwise incompatible with the access control system.

In some embodiments, the access control system includes one or more access control points. Each access control point can include a physical control panel, one or more readers, and one or more access control devices. The physical control panel can be connected to the readers and the access control devices via a hardwired serial connection. The readers can include proximity card readers, biometric readers, keypads, or other input device configured to receive a credential from a user (e.g., by reading an access badge, receiving a PIN, scanning a fingerprint, etc.). The access control devices can include electronic locks, actuators, or other controllable devices that can be operated to automatically grant or deny access through the access control points. For example, a door access control point can include an electronic lock configured to lock and unlock the door in response to a control signal from the physical control panel.

In some embodiments, the physical control panel can receive the credential data from the reader and send the credential data to a central access control host (e.g., an access control server). The access control host can determine whether to grant or deny access by comparing the credential to an access control list. The access control host can send a result of the determination (e.g., grant or deny access) to the physical control panel, which operates the access control devices accordingly. For example, the physical control panel can unlock an electronic lock in response to receiving a control signal from the access control host.

Referring now to <FIG>, an access control system <NUM> is depicted. Access control system <NUM> monitors and controls access to various locations in or around a building (e.g., rooms or zones in a building, parking structures, etc.) using a collection of access control points. Each access control point is shown to include a physical control panel <NUM>, a reader <NUM>, and an access control device <NUM>. Physical control panels <NUM> can be connected to readers <NUM> and access control devices <NUM> via a hardwired serial connection (e.g., RS-<NUM> serial communication lines).

Readers <NUM> can receive credential data from a user via an access control card of a user. For example, readers <NUM> can read a smartcard (e.g., in integrated circuit card) possessed by a user to automatically obtain the credential data, such as an identifier of the user (user ID), from the smart card. The reader <NUM> can receive the user ID based on receiving a personal identification number (PIN). The reader <NUM> can receive the user ID based on biometric data (e.g., using facial recognition, gait recognition, iris recognition, fingerprint recognition). The reader <NUM> can receive the user ID from several of such sources (e.g., smart card, PIN, biometric data).

Access control devices <NUM> can include electronic locks, actuators, or other controllable devices that can be operated to automatically grant or deny access through the access control points. For example, a door access control point can include an electronic lock configured to lock and unlock the door in response to a control signal from the physical control panel. In some embodiments, access control devices <NUM> are distributed throughout a building or campus (i.e., a group of buildings). Each access control device <NUM> can be configured to control a particular access point (e.g., a doorway, a parking structure, a building entrance or exit, etc.).

User interactions with readers <NUM> (i.e., access requests) can be recorded as events and sent to access control host <NUM> via a communications network <NUM> (e.g., a TCP/IP network, a building automation and control network, a LAN, a WAN, etc.). Each event may include, for example, a timestamp, a device ID identifying the access control device <NUM>, a security credential provided by the user at the access point (e.g., a smartcard ID, an access code, etc.), a user ID, and/or any other information describing the access request. Access control host <NUM> can process the events and determine whether to allow or deny the access request. In some embodiments, access control host <NUM> accesses a security database to determine whether the security credential provided by the user matches a stored security credential. In some embodiments, access control host <NUM> determines whether the user associated with the access request (e.g., defined by the user ID or smartcard ID) is authorized to access the area controlled by the access control device <NUM>. In some embodiments, access control host <NUM> displays an alarm or prompt for a security workstation (e.g., a computer operated by security personnel) to allow or deny the access request.

Various devices described herein, including the access control host <NUM> and the load control systems <NUM>, <NUM> described below, can include a processing circuit and/or a communications circuit. The processing circuit can include a processor and memory. The processor can be a general purpose or specific purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable processing components. The processor can execute computer code or instructions stored in memory or received from other computer readable media (e.g., CDROM, network storage, a remote server, etc.). The memory can include one or more devices (e.g., memory units, memory devices, storage devices, etc.) for storing data and/or computer code for completing and/or facilitating the various processes described in the present disclosure. Memory can include random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and/or computer instructions. Memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. Memory can be communicably connected to processor via processing circuit and may include computer code for executing (e.g., by the processor) one or more processes described herein. When processor executes instructions stored in memory, the processor generally configures the processing circuit) to complete such activities.

The communications circuit can include wired or wireless interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.) for conducting data communications with various systems, devices, or networks. For example, the communications circuit can include an Ethernet card and port for sending and receiving data via an Ethernet-based communications network. As another example, the communications circuit can include a WiFi transceiver for communicating via a wireless communications network. The communications circuit can communicate via local area networks (e.g., a building LAN), wide area networks (e.g., the Internet, a cellular network, etc.), and/or conduct direct communications (e.g., NFC, Bluetooth, etc.). In various embodiments, the communications circuit can conduct wired and/or wireless communications. For example, the communications circuit can include one or more wireless transceivers (e.g., a Wi-Fi transceiver, a Bluetooth transceiver, a NFC transceiver, a cellular transceiver, etc.) for communicating with access control host <NUM> via communications network <NUM>.

Referring now to <FIG>, a load control system <NUM> is depicted. The load control system <NUM> can be implemented by and/or using features of the access control system <NUM> described with reference to <FIG>. The load control system <NUM> can be implemented to selectively power loads that may not be part of an access control system. The load control system <NUM> includes a supply controller <NUM> coupled to a switch <NUM> coupled to a power supply <NUM>. The supply controller <NUM> can include a microcontroller. The supply controller <NUM> can control operation of the switch <NUM> to selectively deliver power <NUM> from the power supply <NUM>. The switch <NUM> can include an electronic switch that can change from an ON state to an OFF state (and/or vice-versa) responsive to receiving a switch control signal <NUM> from the supply controller <NUM>. The switch <NUM> can include a relay switch. The switch <NUM> can include a field effect transistor (FET) switch.

The power supply <NUM> can include a portable power source, such as a battery. The power supply <NUM> can include a connection to a remote power source, such as mains power. As depicted in <FIG>, the power supply <NUM> and supply controller <NUM> can be coupled to ground <NUM>. In some embodiments, the power supply <NUM> includes a current limiter. The supply controller <NUM> can control operation of the current limiter to cause the power supply <NUM> to deliver power <NUM> up to a threshold amount unless an output condition is satisfied. As described herein, the supply controller <NUM> can verify security of load <NUM> to determine whether the output condition is satisfied (and thus determine to allow the power supply <NUM> to deliver full power for use by load <NUM>).

The access control system <NUM> can include at least one sensor <NUM> coupled to the switch <NUM> and the supply controller <NUM>. The at least one sensor <NUM> can detect a current <NUM> and a voltage <NUM> associated with the power <NUM> delivered from the power supply <NUM>. For example, the at least one sensor <NUM> can detect a current being delivered to load <NUM>; the at least one sensor <NUM> can detect a voltage being suppled at an output of the supply controller <NUM>. In some embodiments, the at least one sensor <NUM> includes at least one analog-to-digital converter (ADC) that samples an electrical signal and outputs a digital signal corresponding to the electrical signal to the supply controller <NUM> for digital processing by the supply controller <NUM>.

In some embodiments, power <NUM> is delivered from the power supply <NUM> via a circuit path <NUM> for use by a load <NUM> (e.g., a lock; a powered load). The circuit path <NUM> can include an electrical cable. The circuit path <NUM> can be relatively long, enabling ease of installation and usage of the access control system <NUM>. In some embodiments, the circuit path <NUM> includes a first connection-a positive voltage connection that delivers current-and a second connection-a zero voltage connection through which the current returns. As such, the circuit path <NUM> can be analogous to existing connections between the power supply <NUM> and the load <NUM>, enabling the access control system <NUM> to be retrofit into existing systems with no cost increase associated with increased wiring.

As depicted in <FIG>, a load controller <NUM> is coupled to the circuit path <NUM> and a switch <NUM> coupled to the load <NUM>. A current return path <NUM> couples the load <NUM> to the load controller <NUM>, the load controller <NUM> to the circuit path <NUM>, and the circuit path <NUM> to the supply controller <NUM>. The load controller <NUM> can be similar to the supply controller <NUM>. For example, the load controller <NUM> can be a microcontroller. The load controller <NUM> can modified the state of the switch <NUM> (e.g., switch the switch <NUM> from on to off or vice versa) responsive to detecting an enumeration condition corresponding to operation of the plurality of resistors <NUM> is satisfied. The enumeration condition can include each resistor <NUM> completing its respective enumeration communication; a voltage level associated with operation of the load <NUM> being stable; and/or each timing delay (e.g., as described further with reference to <FIG> and <FIG>) being completed.

The load controller <NUM> can receive the current-limited power <NUM> from the power supply <NUM> and be activated by the current-limited power <NUM>. For example, the threshold amount that the current limiter of the power supply <NUM> limits the current-limited power <NUM> to can be set to a value sufficient to activate the load controller <NUM>, but which may be less than an expected power required to operate the load <NUM>.

The load controller <NUM> can communicate information regarding the load <NUM> using a plurality of resistors <NUM>. For example, the load controller <NUM> can execute an enumeration process using the plurality of resistors <NUM>, in which each resistor <NUM> is caused to output a pre-defined code (e.g., enumeration code). The load controller <NUM> can connect the plurality of resistors <NUM> to the power supply <NUM> (e.g., to use power <NUM> delivered from power supply <NUM>) to draw pre-defined amounts of current from the power supply <NUM>. The load controller <NUM> may maintain a plurality of the pre-defined codes (e.g., at least one code corresponding to each resistor <NUM>) in memory, and retrieve the plurality of pre-defined codes for causing the resistors <NUM> to draw the corresponding pre-defined current from the power supply <NUM>. The pre-defined codes may correspond to various data indicative of the load <NUM>, such as security information, product identifiers, current consumption, and/or operating information. The pre-defined codes can be communicated to the supply controller <NUM> via a return path <NUM>.

The supply controller <NUM> can use the at least one sensor <NUM> to measure the current <NUM> and voltage <NUM> corresponding to the pre-defined current drawn by each resistor <NUM>, and thus to calculate the resistance corresponding to operation of each resistor <NUM> (which corresponds to the enumeration code communicated by each resistor <NUM>). Based on operation of the load controller <NUM> and the plurality of resistors <NUM>, the supply controller <NUM> can receive the plurality of the pre-defined codes from the load controller <NUM>, and evaluate an output condition based on the plurality of pre-defined codes.

In some embodiments, the supply controller <NUM> evaluates the output condition by determining whether the plurality of pre-defined codes match corresponding supply codes (e.g., codes maintained in memory of the supply controller <NUM>). For example, the supply controller <NUM> can compare the resistance value calculated based on the current <NUM> and voltage <NUM> corresponding to operation of each resistor <NUM> to a predetermined resistance value of a supply code, and determine the pre-defined code to match the supply code responsive to the resistance value being equal to (or within a threshold percentage of) the predetermined resistance value.

In some embodiments, the supply controller <NUM> executes a pre-processing operation on the pre-defined codes (e.g., on the resistance values calculated based on the current <NUM> and voltage <NUM>) prior to evaluating the output condition. For example, the supply controller <NUM> can filter the pre-defined codes. The supply controller <NUM> can execute a decryption algorithm corresponding to an encryption algorithm that the supply controller <NUM> expects the load controller <NUM> to use when operating the plurality of resistors <NUM>.

Responsive to determining the output condition to be satisfied, the supply controller <NUM> can connect the load <NUM> to the power supply <NUM> to enable the power supply <NUM> to deliver power <NUM> sufficient for operation of the load <NUM>, such as by deactivating the current limiter of the power supply <NUM>. As such, the supply controller <NUM> can use the pre-defined codes communicated by the load controller <NUM> using the plurality of resistors <NUM> to verify that the load <NUM> can be securely used with the power supply <NUM>, reducing the likelihood of unsafe operations such as brown-outs.

Referring further to <FIG>, in some embodiments, various functions of the load control system <NUM> can be executed using an ASIC. For example, the ASIC can execute the supply controller <NUM> and/or the load controller <NUM>. The load controller <NUM> of the ASIC can include an enumeration module that executes the functionality of the plurality of resistors <NUM>.

Referring now to <FIG>, a timing diagram <NUM> corresponding to operation of the load control system <NUM> is depicted. The load control system <NUM> can perform the depicted operations responsive to receiving a request for power from a load connected to the load control system <NUM>. The load control system <NUM> can perform the depicted operations at various points in time and/or time delays between operations. At <NUM>, prior to startup (e.g., prior to) the request for power and/or connection of the load, the current from the power supply is zero, the load is zero, and the voltage of the power supply is zero. At <NUM>, subsequent to startup, voltage from the power supply (e.g., direct current (DC) voltage) increases to a nominal supply level. At <NUM>, current from the power supply is limited to a first, relatively low limit value, such as to enable over-current protection and/or prevent the load from drawing sufficient power to operate until security of the load has been verified. At <NUM>, the load controller powers up, using the first limited current from the power supply at a nominal operational level <NUM>. At <NUM>, the load controller uses the plurality of resistors to transmit a plurality of enumeration codes <NUM> to the supply controller. At <NUM>, having verified the plurality of enumeration codes, the supply controller increases the current limit from the power supply to a second, relatively high value, to enable the load to operate. At <NUM>, the load controller connects the load to the power supply so that the load can draw an operating current <NUM>.

Referring now to <FIG>, a load control system <NUM> is depicted. The load control system <NUM> can incorporate features of the load control system <NUM> described with reference to <FIG>. Similar to the load control system <NUM>, the load control system <NUM> includes a supply controller <NUM> coupled to a switch <NUM> and power supply <NUM> that delivers power <NUM> via a circuit path <NUM>, and at least one first sensor <NUM> that can detect a first current <NUM> and a first voltage <NUM>. The power supply <NUM> and supply controller <NUM> can be coupled to ground <NUM> via respective current return paths.

The load control system <NUM> includes a plurality of load units <NUM> including a first load unit 410a and at least one second load unit 410b. The supply controller <NUM> can control delivery of power <NUM> to each of the plurality of load units <NUM> based on pre-defined codes received from each of the plurality of load units <NUM>.

The first load unit 410a includes a first load controller 414a coupled to a first switch 418a coupled to a first load 422a. The first load controller 414a can receive current-limited power <NUM> via the circuit path <NUM>, and operate a plurality of first resistors 426a to provide a plurality of first pre-defined codes to the supply controller <NUM>.

The at least one second load unit 410b includes a second load controller 414b coupled to a second switch <NUM> coupled to a second load 422b. The second load controller 414b can receive current-limited power <NUM> via the circuit path <NUM> (and the first load 422a) and circuit path 412b, and operate a plurality of second resistors 426b to provide a plurality of second pre-defined codes to the supply controller <NUM>.

In some embodiments, the load control system <NUM> includes at least one second sensor 430a. The at least one second sensor 430a can detect a second current 434a and a second voltage 438a associated with power delivered to the at least one second load unit 410b (and thus the plurality of second pre-defined codes outputted by the at least one second load unit 410b). As depicted in <FIG>, the second current 434a and second voltage 438a can be communicated via the circuit path <NUM> to the supply controller <NUM> to enable the supply controller <NUM> to evaluate output conditions for each of the plurality of second load units 410b. Additional second load units 410b may similarly be coupled to the depicted second load unit 410b and to sensors that detect current and voltage corresponding to the pre-defined codes outputted using resistors of the additional second load units 410b.

In some embodiments, the plurality of load units <NUM> can execute a sequential procedure to communicate respective pre-defined codes to the supply controller <NUM>. A load unit <NUM> can determine whether it is ready to transmit the pre-defined codes (e.g., based on receiving current-limited power and/or receiving a power request from a corresponding load <NUM>), and transmit the pre-defined codes responsive to determining to be ready. Subsequent to transmitting the pre-defined codes, the load unit <NUM> can activate downstream load unit(s) <NUM>, such as by activating a current measuring switch analogous to the current limiter of the power supply <NUM>. In some embodiments, the load unit <NUM> initiates a timer responsive to transmitting the pre-defined codes, compares the timer to a threshold activation time, and activates the load <NUM> responsive to the timer exceeding the threshold activation time. Each downstream load unit <NUM> can execute similar steps, such that each load unit <NUM> transmits its pre-defined codes, waits for the threshold activation time, and then activates the corresponding load <NUM>; once the supply controller <NUM> has received all of the pre-defined codes (e.g., via current return path <NUM>), the supply controller <NUM> can determine whether to allow connection of each of the downstream loads <NUM>. As depicted in <FIG>, a pair of wires <NUM>, <NUM> can connect each downstream load unit (e.g., second load unit 410b) to each upstream load unit (e.g., first load unit 410a), reducing the wiring and other overhead associated with retrofitting existing systems to operate using the load control system <NUM>.

Referring now to <FIG>, a timing diagram <NUM> corresponding to operation of the load control system <NUM> is depicted. The load control system <NUM> can perform the depicted operations in a similar manner as described with respect to load control system <NUM> and <FIG>, including to selectively provide power to a load based on whether the load is verified. At startup, a voltage <NUM> from the power supply increases to a nominal voltage level <NUM>, a current <NUM> from the power supply is limited to a first, relatively low limit value <NUM> (e.g., by operation of a supply controller), and load controllers of a plurality of load units draws an initial current <NUM> less than the limit value <NUM>. The load controllers use corresponding pluralities of resistors to provide enumeration codes <NUM> to the supply controller. For example, <FIG> depicts each of six load controllers providing enumeration codes to the supply controller. Each load controller may provide various numbers of enumeration codes. Responsive to verifying the received enumeration codes, the supply controller can increase the limit on the current <NUM> to a second, relatively high value <NUM>, subsequent to which the load controllers can connect respective loads to the power supply to draw current <NUM>.

Referring now to <FIG>, a method <NUM> of operating a load control system is depicted. The method <NUM> can be executed using various load control systems described herein, including load control systems <NUM>, <NUM>. The method <NUM> can be performed in accordance with the timing diagrams <NUM>, <NUM>.

At <NUM>, a current limit of a power supply is set to a first value. The current limit can be set by a supply controller. The current limit can be set using a current limiter of the power supply. The first value can be a relatively low value to enable a load controller to operate and less than a value at which a load can operate. The current limit can be set responsive to a load being connected to the load controller.

At <NUM>, the power supply is connected to a load controller to provide power from the power supply to the load controller. For example, the supply controller can set a switch to an ON state. The switch may couple the load controller to the power supply via a circuit path.

At <NUM>, the load controller uses the power from the power supply (e.g., relatively low power) to cause a plurality of resistors to provide a plurality of enumeration codes to the supply controller. The enumeration codes may correspond to various data indicative of a load coupled to the load controller, such as security information, product identifiers, current consumption, and/or operating information.

At <NUM>, the supply controller receives the plurality of enumeration codes. In some embodiments, the supply controller uses at least one sensor to detect a current and a voltage of the enumeration codes, such as to calculate a resistance of each code.

At <NUM>, the supply controller evaluates an output condition responsive to receiving the plurality of enumeration codes. The supply controller can compare the resistance value calculated based on the current and voltage corresponding to operation of each resistor to a predetermined resistance value of a supply code, and determine the pre-defined code to match the supply code responsive to the resistance value being equal to (or within a threshold percentage of) the predetermined resistance value. In some embodiments, the supply controller executes a pre-processing operation on the pre-defined codes (e.g., on the resistance values calculated based on the current and voltage) prior to evaluating the output condition. For example, the supply controller can filter the pre-defined codes. The supply controller can execute a decryption algorithm corresponding to an encryption algorithm that the supply controller expects the load controller to use when operating the plurality of resistors.

At <NUM>, responsive to determining the plurality of enumeration codes to satisfy the output condition, the supply controller can connect the load to the power supply. For example, the supply controller can modify a current limit of the power supply to a second value greater than the first value and/or deactivate the current limit. Responsive to determining the plurality of enumeration codes to not satisfy the output condition, the supply controller may take various actions. As depicted by the dashed line in <FIG>, the supply controller may continue to evaluate enumeration codes responsive to determining the plurality of enumeration codes to not satisfy the output condition; the supply controller may disconnect the power supply from the load and/or load controller; output an alert indicating the output condition was not satisfied; and/or modify the current limit of the power supply.

In some embodiments, the supply controller receives a plurality of enumeration codes from each of a plurality of load controllers. Each load controller may cause a corresponding plurality of resistors to output the respective enumeration codes. In some embodiments, additional sensors may be used to detect current and/or voltage of each enumeration code for evaluation by the supply controller. In some embodiments, each load controller may wait a predetermined delay subsequent to outputting the plurality of enumeration codes prior to connecting a respective load to the power supply.

The construction and arrangement of the systems and methods as shown in the various embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present appended claims.

The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present appended claims.

Claim 1:
A load control system (<NUM>) for access control, comprising:
a power supply (<NUM>);
a load controller (<NUM>) configured to be coupled to a load, the load controller (<NUM>) configured to receive a first power having a first current level from the power supply (<NUM>), and to communicate information regarding the load by executing an enumeration process using a plurality of resistors (<NUM>), in which each resistor (<NUM>) is caused to output a pre-defined code, and by connecting each of the plurality of resistors (<NUM>) to the power supply (<NUM>) to cause the plurality of resistors (<NUM>) to draw pre-defined amounts of current from the power supply (<NUM>) and output a plurality of pre-defined codes; and characterised in that
a supply controller (<NUM>) that is configured to receive the plurality of pre-defined codes, evaluate an output condition based on matching the plurality of pre-defined codes to a plurality of corresponding supply codes, and cause the power supply (<NUM>) to output a second power having a second current level greater than the first level responsive to the plurality of pre-defined codes satisfying the output condition.