https://devzone.nordicsemi.com/f/nordic-q-a/18931/changing-connection-interval-after-connection-establishedHi, the system that i designed based on nRF51822 have two mode : the first mode is the normal mode where the nrf should have a high connection interval of 2 to 3 seconds in order to save the power. The nrf should collect data from the on-board sensorsen-USTelligent Community 13Thu, 12 Jan 2017 10:24:18 GMThttps://devzone.nordicsemi.com/thread/73166?ContentTypeID=1Thu, 12 Jan 2017 10:24:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3cece1b3-8fb2-4354-ba40-065a0b1548f4Petter Myhre<p>It is possible to change it after connecting. What SDK are you using? Are you using the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v12.2.0/lib_ble_conn_params.html?cp=4_0_1_3_1_3">Connection Parameters Negotiation</a> module? I also recommend monitoring the actual connection interval you are using. See <a href="https://devzone.nordicsemi.com/question/56471/check-ble-connection-interval/">this</a> for more info.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/73165?ContentTypeID=1Thu, 12 Jan 2017 07:18:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e427ef46-9991-44dd-9475-719858559ee2is<p>Try to use sd_ble_gap_conn_param_update().</p><div style="clear:both;"></div>