Best place to put sd_ble_gap_tx_power_set() to reduce power during bonding?

[mnsk]

Hi,

I am using peer manager to use static passkey with nrf51822, sdk11 and s130 v2.

Is the "case PM_EVT_CONN_SEC_START:" the best place to put sd_ble_gap_tx_power_set() to reduce power during bonding to avoid MITM attack and then increasing it again in the "case PM_EVT_CONN_SEC_SUCCEEDED:"?

I thought to increase the power back in "BLE_GAP_EVT_CONNECTED" event but it is also being called along with "PM_EVT_CONN_SEC_START" event.

[FormerMember]

I would say that the TX power could be reduced as early as when the device is advertising. Why?

1. If advertising with lower output power, fewer devices will have a chance to know that the advertising device is nearby. In addition, the scanner will need to be able to pick up advertising packets at the low TX power to be able to maintain a connection with the low TX power level.
2. If reducing the TX power after connected, there could be a chance that the TX power is too low for maintaining a connection.

[mnsk]

I am designing a system in which a user can control the device from a distance but for bonding he has to be near the device. If I lower the TX power before advertising the user has to be near the device every time he needs to be connected after bonding. That's why I will increase the power back in connection and during advertising.