5.4.4.4 Query as Client by Service (QCS[,<hex16 Connection Handle>])

Format: QCS[,<hex16>]

Use command QCS to start GATT service discovery from the GATT client.

The RNBD451 module starts as a GATT server by default. If the user also prefers the RNBD451 module to act as a GATT client, the command QCS must be issued first.

Command QCS performs the essential service discovery process with the remote GATT server and acquires supported public and private services and characteristics on the remote GATT server. The RNBD451 module supports up to six client public services and four client private services. Each client service is able to define up to eight characteristics. A connection with the remote GATT server must be established before using the command QCS. The command has an option parameter that is a connection handle to indicate a specific link for multiple links.

Command QCS retrieves critical client information from the remote GATT server; therefore, it is a prerequisite over any Client Service related commands, such as LC, CHR and CHW.