User's Manual Part 2

4.7: Bluetooth Security Chapter 4: Configuration and Operation

M S

S S

A master can:

•

Setup a connection to another device.

• Perform searches.

• Accept connections from other devices.

A slave cannot:

• Connect to another device.

• Perform searches.

•

Accept connections from other devices.

There are a few settings and parameters that affect how the roles master and slave

are assigned to the devices communicating.

First, it is possible for a device to request to become the master when another de-

vice connects to it. This setting is called the master/slave role policy. Use the

“Write_MasterSlaveRole_Policy” command to set the policy to either:

•

0, the device will request to become the master every time another device

tries to connect.

• 1, the device will become the slave every time another device tries to con-

nect.

Second, when connecting to another device using the “Con-

nect_To_Serial_Service” command the parameter <must_be_master> indicates

whether or not the connecting device allows the server to become the master of

the connection.

NOTE: If <must_be_master> is 1 and the server has set master/slave role policy to 0

(become master) the connection will

not

be established.

If you do not specifically need to become the master the <must_be_master> pa-

rameter should be set to 0 to allow the server to select which role to take.

4.7 Bluetooth Security

Bluetooth has support for security. The Bluetooth security is based on authentica-

tion during connection establishment and encryption of sent and received data.

Security Modes

A Bluetooth device can be in two different security modes, security enabled (au-

thentication and encryption turned on) and security disabled (authentication and

encryption turned off). If at least one of the two devices wanting to communicate

has security enabled, security will be used. Use the “Write_Security_Mode” com-

mand to set the security mode for the device.

Only the highest security level, security level 3 (link level security) and not security

level 2 (service level), is supported.