Adder Technology AV4USB-MAC, AV4USB-PC Setting the USB enumeration guard time option switches 5

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2.4.1Setting the USB enumeration guard time (option switches 5 and 6)

A USB-enabled computer detects and configures USB peripherals when they are connected to or disconnected from its USB ports. This process is called enumeration. You can often see when the enumeration process is in progress as the computer will usually display a timer or hourglass for a few seconds after the connection of a USB peripheral whilst the device is being enumerated.

This enumeration process will take place each time that the AdderView locks on to a new computer port. Unfortunately computer software is not generally robust enough to cope with the connection between the computer and peripherals being broken during this enumeration process. If the connection is lost part of the way through the enumeration process then the computer software or the peripherals can hang.

To overcome this problem the AdderView is fitted with an enumeration guard timeout system. Once the AdderLink has locked on to a channel it will remain connected to that channel for at least the enumeration guard time. This ensures that the enumeration process is complete before further channel changes are allowed and consequently ensures robust and reliable operation.

The enumeration process takes longer if more peripherals are connected. Select an enumeration time that is longer than the longest observed enumeration time. The enumeration time can be judged by the length of time that the hourglass or timer remains on the computer screen after a channel change (normally a few seconds). Alternatively you may select the shortest enumeration guard time (2 seconds) and remember not to change the channel whilst the hourglass or timer is displayed.

2.4.2 Setting the autoscan dwell time

The AdderView may be made to autoscan the connected computers. During autoscan the AdderView displays the video signal from each computer in turn for a selected time period. This time period is known as the dwell time and may be selected to be 2 or 5 seconds using option switch 7. Ports are scanned in ascending numerical sequence and all the ports or just the active ports will be scanned according to the setting of option switch 8.

AdderView USB

Installation and Use

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Contents ADDERView USB Safety information About this manualWarranty TrademarksRadio Frequency Energy European EMC directive 89/336/EECContents Using the AdderView Cable and connector specificationsIntroduction Key featuresPC and MAC models Remote controller contents part code AVremote AdderView USB mode AV4USB-PC Product informationAdderView USB model AV4USB-MAC Installation What you will needConnecting your devices Mounting the AdderView AdderView USB Installation and Use AdderView USB Installation and Use Configuring the AdderView Setting the USB enumeration guard time option switches 5 Setting the autoscan dwell timeSetting the keyboard hotkey combination model AV4USB-PC only Powering on the AdderView Configuring your computersRe-enabling a disconnected PS/2 mouse AV4USB-PC only Power on status Using the AdderViewFront panel key Switching between computers using the AdderView Status displayKeyboard hotkey control model AV4USB-PC only AdderView USB Installation and Use Optional remote controller Autoscan modeMouse control model AV4USB-PC only PC and Macintosh keyboard equivalent key mappings Querying the AdderView’s firmware versionIBM 104/105-key Apple keyboard Keyboard A1. USB cables Appendix A. Cable specificationsA2. Video cables A4. Remote controller extension cables A3. PS/2 style keyboard and mouse extension cablesProblem Appendix B. Problem SolvingAction AdderView USB Installation and Use AdderView USB Installation and Use S TA L L AT I O N & U S E