PRIMARY_SERVICE, GAP_SERVICE
CHARACTERISTIC, GAP_DEVICE_NAME, READ, "BTstack"
CHARACTERISTIC, GAP_APPEARANCE, READ, 00 00

PRIMARY_SERVICE, GATT_SERVICE
CHARACTERISTIC, GATT_SERVICE_CHANGED, READ,

PRIMARY_SERVICE, FFF0
CHARACTERISTIC, FFF1, READ | WRITE | AUTHENTICATION_REQUIRED, "A"

// GAP/SEC/CSIGN/BV-02-C expects a READ + Signed Write
CHARACTERISTIC, FFFB, READ | AUTHENTICATED_SIGNED_WRITE | DYNAMIC

// GAP/SEC/SEM/BV-22-C requires write + authentication
CHARACTERISTIC, FFFD,  READ | WRITE | AUTHENTICATION_REQUIRED | DYNAMIC

// GAP/SEC/SEM/BV-39-C requires write + encrypted
CHARACTERISTIC, FFFE,  READ | WRITE | ENCRYPTION_KEY_SIZE_16 | DYNAMIC