The values set in the
Authentication
PIN field will vary depending on the Bluetooth version of the central device. If the central uses BT v2.0 or older, enter a numeric value in this field. You are prompted to enter this same value on the central device to verify the pairing.
Security Mode
2 or 3 in
Advanced Settings
should also be selected for PIN paring. In Advanced Settings, select Security Mode 2 or 3 for PIN paring.