Product Specs

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the role of “Slave”. “Master” devices will initiate commands and requests to “Slave”

devices which will respond.

One of the first task of a Bluetooth LE application, such as on a smartphone app, is to

discover other Bluetooth LE devices that it can connect to.

1.1.2 Services

Once a device has been discovered the next task is to figure out what services are

offered by the device. So, what’s a service? Well, a service consists of:

 A Service Specification, which consists of:

o A collection of characteristics;

o References to other service.

Figure 4 is giving an visualization to help cement the concept of services and

characteristics. When talking about services we use the names:

 GATT Server

 GATT Client

This highlights the client/server model that is used at this level of the architecture.

Figure 4.

Let’s move on to the differences between a GATT server and a GATT client

A GATT client is a device which accesses data on the remote GATT server via read,

write, notify, or indicate operations.

A GATT server is a device which stores data locally and provides data access

methods to a remote GATT client.