Finally, I think we have managed to "close the chapter" in the miserable quest for accurate information to allow for proper compilation of the USB-related audio channel drivers, regarding the "proc/sys file structure" of various Linux kernels, etc. As it turns out, the "major" change in that area happened in Linux Kernel 2.6.20, as the new release of ALSA at that time (1.0.19) did some changes in that area. In addition, to allow for "backwards compatibility", a new kernel parameter (CONFIG_SYSFS_DEPRECATED) was added to allow for "newer" kernels to use the "old structure" for the /sys filesystem entries. So, all of the Centos 5.X kernels, are 2.6.18-based, and are pre-changes. Limey Linux, which is a 2.6.30 kernel, has the CONFIG_SYSFS_DEPRECATED parameter enabled, so it "acts" like a pre 2.6.20 kernel in that repsect also. Pickle, is a 2.6.35 (as I recall), and follows the "current" way of doing things. Now, the build scripts and sources (in SVN) take all this into account, and seem to properly build in all the OS's that we support. Since this is (hopefully) *FINALLY* done, it would be nice to "move on" to the next UTTERLY MISERABLE festering technical issue with app_rpt: The fact that the OSS audio support in the newer kernels (like the one used in Centos 6.X) seems to be SERIOUSLY broken. It is entirely possible that if chan_simpleusb and chan_usbradio were modified to use ALSA directly, instead of using the OSS compatibility layer (as it does now), it *MIGHT* fix this problem (and might also allow newer ARM implementations, such as the Pi, etc) to work properly, at least with chan_simpleusb. This is not, by any means, a simple task. Nor does it even guarantee that it will do any good. We don't *KNOW* that this is problem. It just seems like a reasonable guess at this point. Is there anyone out there that is capable and willing to attempt to port (particularly chan_simpleusb at first) to "native ALSA"?? It sure would be nice. I am EXTREMELY BUSY and just can't do everything here (technically). Jim WB6NIL