The remote control may use a variety of wireless transmission mediums in order to send or transmit the generated control signal from the remote control to the receiving electronic device. Remote controls are operable through either radio frequency or an infrared (IR) link to transmit control signals to the device to be controlled. Many such remote controls transmit an infrared signal that is obtained by pulse period modulation (PPM) or alternatively known as space width modulation (SWM) or variable space modulation (VSM) of a carrier wave. IR transmissions from a remote control are typically made up of a series of pulses (high voltage/binary 1) and spaces (low voltage/binary 0) of varying lengths. Different combinations of the pulses and spaces are used to create unique IR codes. Each unique IR code represents a different key on the remote control. A typical remote control system for controlling the operation of electrical apparatus has two parts. The first part is a receiver provided at the apparatus under control, and the second part is a transmitter for generating and transmitting a control signal for receipt by the receiver to control the apparatus. A remote control includes transmitter circuitry that may be part of an integrated circuit (IC) and, more particularly, an application specific integrated circuit (ASIC). For typical transmissions utilizing the IR circuitry, the length of the pulse and the length of the space are individually specified in separate registers. The registers are loaded with a pulse/space combination when a key on the remote control is actuated. When an IR sequence is being transmitted, an interrupt is generated at the end of each pulse-space combination. At the time of the interrupt, the next pulse-space sequence or combination is loaded from user registers to transmission registers. The consumer electronic device may include a microprocessor for performing many receiver functions in addition to decoding received IR coded command signals and generating appropriate control signals in response thereto. The transmitter also includes keys, buttons and/or switches for operation, which increase the production cost of the overall transmitter and their design cannot be changed.

The remote control unit has stored patterns corresponding to push buttons assigned to various functions of the controlled device. Activating a button causes the excitation of the photo emitter diode according to the stored pattern, thereby generating and transmitting a control signal. Typical remote control devices, particularly the remote control devices for controlling the televisions, include an up key and a down key to change the channels in series and to select the required channels one by one. The remote control unit can be used to either power up/down the controllable device, raise or lower the volume of a receiver, change channels, as well as provide other commands suitable for the device being controlled. In response to a user input, the controller generates an appropriate remote control signal using look up tables, and the like, from memory and causes the signal transmitting circuit to transmit the remote control signal. The signal transmitting circuit may be designed to transmit the remote control signal in a number of different forms, including, but not limited to, an IR signal and a RF signal. The infrared devices generally comprise a housing having one or more buttons or switches which serve as the user interface, one or more integrated circuits, often accompanied by a ROM (read only memory) or EPROM (erasable and programmable read only memory) to translate the user command to a digital or binary signal, an infrared light emitting diode (LED) and associated driver circuitry, a power source (usually batteries), and, optionally, a visible LED to signal the user when the remote control unit has power and/or is transmitting. The infrared LED typically emits a series of binary signals distinguished by the time duration of, or between, bursts of pulses, usually in the millisecond range. The format of the IR signal is determined by the manufacturer for each model and many such formats are known and used. Each format specifies a set of signal characteristic, which include signal duration, transmission and pause intervals, carrier frequency, pulse width and pulse modulation. Another method of sending remote control signals is to transmit the signals in RF form. RF signals are generally non-directional and have greater range than IR signals. RF signals may also be transmitted through objects such as walls so that the user can use the remote control device to control a device in a separate room. RF signal formats generally have wider bandwidths than IR signal formats.

A universal remote control unit has a plurality of reference or operating modes for controlling a plurality of devices. Each operating mode of the universal remote control unit enables the user to remotely control each of the devices. A remote control device typically controls a selected electronic consumer device by transmitting infrared operational signals to the selected electronic consumer device. The operational signals contain key codes of a codeset associated with the selected electronic consumer device. Each key code corresponds to a function of the selected electronic consumer device, such as power on, power off, volume up, volume down, mute, play, stop, select, channel up, channel down, etc. A universal remote control unit includes a plurality of mode push buttons which correspond to the different devices to be controlled. The mode push buttons are used to directly change the operating mode of a corresponding device. Each operating mode enables the user to remotely control a corresponding device. The universal remote control unit is provided to a particular user essentially "empty" of the code data needed to configure the remote control to that user's television, video cassette recorder, cable box, Internet access device or other electronic device. The universal remote control is built with a reader slot or port into which the user can insert separately purchased "device library" cards which contain the sets of code data necessary to configure the remote control to operate all or some of those electronic devices the user wishes to control. Additional sets of code data can be added to the remote control any time the user obtains a new electronic device, up to the maximum capacity of the remote control. Generally, the universal remote control must be set to a learning mode and repetitively a key of the universal remote control is selected and a corresponding key of the other remote control is pressed, causing a command code to be transmitted to the universal remote control and associated with the selected key.

Universal remote controls can be programmed by a user to operate one of a plurality of different types of electronic devices produced by different manufacturers. Due to their programmability, consumers frequently use universal remote controls to replace lost remote controls and as a single control device for controlling a number of separate audio/video components. A universal remote control is programmed by entering a reference code associated with an electronic device to be controlled into a memory device of the universal remote control. The reference code identifies the electronic device type and manufacturer and allows the universal remote control to transmit control signals having the proper signal structure to the device to be controlled. The proper signal structure is determined by characteristics which include, but are not limited to, carrier frequency, pulse width, pulse modulation and overall timing. A universal remote control will store or otherwise be associated with a code set for each controllable device that it controls. A code set is a group of commands that operate a controllable device. The code sets commonly vary for each type and brand of controllable device. Typically, a user of a universal remote control is provided with a manual which includes code sets for a plurality of source remote controls. The user has to determine the correct code set corresponding to each source remote control (SRC) to be programmed into the universal remote control (URC), then manually enter that code set into the URC. Some universal remote controls have the capability of being programmed without requiring the user to manually enter a code set. This type of URC is typically able to operate in a "learning mode," where the URC is able to duplicate a signal received from each key of a SRC and store that signal in memory.