EKP> I have pasted the lines quoted by DDK regarding this.. EKP> I did not understand thr paragraph which says EKP> "The limitation on the number of device interfaces EKP> does not limit the number of devices. A subsystem EKP> driver that manages several devices (four MIDI EKP> devices, for instance) still requires only a single EKP> device interface." EKP> Does the above paragraph indicates that there can be EKP> 32 interfaces but each interface can have devices EKP> without limits ? 1 interface == 1 filter how you construct you filter is all up to you, but normally 1 filter means 1 stereo IN/OUT pair EKP> Then the list shown in "control EKP> panel->sounds and audio devices" are interfaces or EKP> devices ? If you look from drivers point of view a device is normally a "hardware device" (it contains everything), when interface is a filter or part of your "hardware device". ex.: your hardware device contains 4 INs and 4 OUTs and 1 MIDI in and out. So you'll end up with 3 filters ( 2INs+2OUTs = 1 filter, 2INs+2OUTs = 1 filter, 1 MIDI IN+OUT = 1 filter) EKP> what is the API call used to add several EKP> devices to one interface ? it's in other order: device -> interface=filter-> pin ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.de/