Most a/v equipment requires a delay after you turn them on before they will respond to other commands. For example, if you turn your receiver or tv on, it may be 5 seconds or more before it responds to any other commands. If this is the case, put the number of seconds in the 'power delay' box. When LinuxMCE turns the device on, it will hold up any other commands for that many seconds to give the device time.
Some a/v equipment have the same issue when you change inputs. If you turn your tv from input #1 to input #3, it may need a couple seconds to 'stabilize' before it is ready to respond to other commands. If so, indicate how many seconds in the 'IR Mode Delay' box.
If this device accepts numeric digits, such as a cable box or TV that tunes channels, or a receiver that tunes stations, you may need to specify a Digit Delay. If LinuxMCE sends the codes too fast your device may miss some digits. If you put a number in this box, LinuxMCE will delay that many milliseconds in between digits. Note that milliseconds are 1/1,000'ths of a second. So putting 1000 in the box means LinuxMCE will wait 1 second in between digits. Putting in 250 means a delay of a quarter second.
If the device takes numeric digits, you need to tell LinuxMCE how to terminate, or how to tell the device that it is finished and to tune right away. Some devices have an 'ENTER' key. If you press '1' '2' and then 'ENTER' on your remote control to tune to channel 12, choose the Terminate with Enter key option. LinuxMCE will then send an enter key after it sends the digits. Other devices don't have an enter key and require to pad the digits with 0's if you want it to tune right away. If you enter '0' '1' '2' on your remote to tune to channel 12 and '0' '0' '2' to tune to channel 2, then you would choose Terminate with 'padded 0's' and specify 3 digits.
Most a/v devices often are often interconnected. For example, your DVD player's video outputs may be connected to a TV, and the audio outputs to a receiver. When you want to watch a DVD, the DVD player must be turned on, the TV must be turned on and set to the correct input, and the same for the receiver. Most smart home systems require you to create complicated macros to do this series of tasks. With LinuxMCE, however, all you need to do is indicate how the devices are connected using the 'connection wizard', and LinuxMCE will figure out what commands to send on its own.
This does mean that LinuxMCE needs to know what inputs and outputs your device supports so that it can show them on the connection wizard. If your model of a/v device was not already in the database and you added it yourself, you will need to use the a/v properties page to provide this information for your model. Very few devices have an 'output selection'. Unless your device requires a command to turn on a particular output you can ignore the 'output' section. Sometimes video scalers have specific outputs.
Normally only TV's, Receivers and Amplifiers have 'inputs' that need to be selected. If you have a device that does not have 'inputs' you can also ignore the input selection. Otherwise, the column on the left lists all standard inputs that your type of device may have. Choose the ones that your device actually has and move them to the column on the right. You may need to press the 'input select' button on your remote to see all the inputs your device supports. Hopefully your device supports discrete inputs, since it will work much better if it does. If you don't know what that means, TOAD vs Discrete Codes. If your device does support discrete input codes and requires an 'input select' command to toggle inputs, be sure to check the appropriate 'toggle' button. In that case you must be sure that the inputs are listed in the correct order since LinuxMCE will need to toggle through all the inputs to find the right one. If your device supports discrete inputs, you will be able to learn the codes for all the discrete inputs on the IR codes page. If your device only works with toggle, then you will need to learn the toggle 'input select' command on the IR codes page.
Most receivers have DSP modes--Digital Signal Processing--like "Dolby Digital", or "Jazz Club". If so, choose the DSP modes your device supports. When setting up your media scenarios, you will then be able to indicate what DSP mode you want LinuxMCE to select for each type of media.