https://devzone.nordicsemi.com/f/nordic-q-a/127559/request_cb-callbackHI I’m currently using NCS 3.2.1 , working with the periodic_adv_conn sample. On the advertiser side, after receiving data from a node during each periodic sync broadcast, I want to include that node’s information in the next periodic advertisingen-USTelligent Community 13Wed, 25 Mar 2026 16:05:23 GMThttps://devzone.nordicsemi.com/thread/564053?ContentTypeID=1Wed, 25 Mar 2026 16:05:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:919ee429-6028-4e8c-b621-5fcdd2d91d6etesc<p>Hi,</p> [quote user=""]How long in advance of the actual periodic advertising transmission does the <code>request_cb</code> callback get triggered?[/quote] <p>The controller raises this event when it has buffer space ready. This can be up to one periodic interval before the requested data will be sent. The precise timing depends a bit on number of buffers and number of subevents configured. When the callback is called depends on what other threads are running, since the host has to pull the HCI event from thread mode.</p> <p>Regards,<br />Terje</p><div style="clear:both;"></div>