https://devzone.nordicsemi.com/f/nordic-q-a/45763/communication-between-master-and-slave-devices-sdk15-0-or-sdk15-2Now, I have a project that needs to do a master device to communicate with another slave device, but the slave device is done by the customer. I found that my main device wasn&#39;t communicating properly, so I changed the cccd_configure function in nus_cen-USTelligent Community 13Tue, 09 Apr 2019 10:20:22 GMThttps://devzone.nordicsemi.com/thread/180983?ContentTypeID=1Tue, 09 Apr 2019 10:20:22 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3eda8482-dc3d-4232-90d4-35259c20b3c8run_ar<p>HI,</p> <p>It&#39;s hard to say exactly what changed on the peripheral. But might be that the CCCD is not correctly configured. You could check with a sniffer to see if write request is supported. As far as I can remember it should be write request and not write command when writing to the CCCD, but I think it is up to the application to configure this. I.e. the Softdevice probably does not enforce this.</p><div style="clear:both;"></div>