The iMate driver provides the functionality of the ADB manager. This allows ADB devices that require custom drivers to operate on an iMac or a Mac with a USB card. Many ADB devices such as keyboards, mice, and bar code readers operate with the iMate without any driver software at all or only need a driver to support special functions. You would only need to download the iMate driver for devices with custom drivers.
iMac Firmware 1.x Updater