In my CBCharacteristicWriteWithResponse I'm getting called back immediately with an error: Error Domain=CBErrorDomain Code=0 "Unknown error." I get this both in the sim and on the device. The BLE112 config for the characteristic in question is: <characteristic uuid="76ea007c-4997-46d3-8280-dd850b8c2f9a" id="command"> <description>Command</description> <properties read="false" write="true" authenticated_write="true" /> <value length="1" type="hex">0</value> </characteristic> Other characteristics marked with authenticated_write="true" seem to write okay. -- Rick _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists.... This email sent to site_archiver@lists.apple.com