ANCS characteristics changed

[Paul Yip]

We found that in some cases. e.g. we started a background ble service. The ancs characteristics will change as the picture below. Do you think it's normal? Does the Nordic's ANCS sample source handle this problem? Thanks.

[Krishna Shingala]

Hi Paul,

By specification, for a bonded device, it is not permitted to change the handles of GATT Server record without notifying the GATT Client (ANCS) using the service changed characteristics.

However, currently ANCS does not handle service changed notification nor configures this characteristic on the peer. Application must handle this itself.

Hope this helps!

Regards, Krishna

[Paul Yip]

Hi Krishna,

We implemented the service changed in our app. The first time we set the CCCD okay. After the handle changed, we set the CCCD for the new handle failed. The followings are the log for wireshark.

It looks like there is a security issue after service change. Do you think we could solve? Thanks.

Paul