https://devzone.nordicsemi.com/f/nordic-q-a/66113/why-i-cannot-see-data-on-my-phone-app-even-when-notifications-enabled-on-both-tx-and-rx-characteristics-in-my-server-side-codeHello I have an interesting problem from the ble_app_uart example modified to work with spis. ble_nus.c code In the ble_nus.c code (above) I modified to enable notifications (both on RX and TX characteristic) from the peripheral (nRF device) sideen-USTelligent Community 13Mon, 21 Sep 2020 12:01:43 GMThttps://devzone.nordicsemi.com/thread/270572?ContentTypeID=1Mon, 21 Sep 2020 12:01:43 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9fd96fd3-9838-4582-9e02-c67cc1b7a044Kenneth<p>I am not sure it is a good idea or straight forward to change the logic of the NUS service by changing a characteristic that was by default intended for a&nbsp;handle for the peer to write to, to a characteristic that should now be used in the opposite direction with notification. It seems here that you already have a proprietary characteristic that can notify data, why not just add a small header to that packet to identify the type of notification data that is in the packet? I do not see a clear advantage of having multiple proprietary notifications, they will any case be sent in the order they are written to the softdevice over the BLE link. If you need a second characteristic to notify data I think I would recommend to add a new characteristic to avoid possible issues with the state machine in the NUS service.&nbsp;</p> <p>Best regards,<br />Kenneth</p><div style="clear:both;"></div>