Where <bdaddr_m> is optional. If it is not specified, then the slave unit will accept connections from any device. If specified then only connections from the device specified will be accepted.
If it is desired that the slave unit not be discoverable (the master is by default not discoverable), then the configuration commands are,
AT&F
ATS512=3AT&W
AT+BTR<bdaddr_m>
Where <bdaddr_m> is optional. If it is not specified, then the slave unit will accept connections from any device. If specified then only connections from the device specified will be accepted.
When the units are next power cycled, the slave unit will wait for the master to connect to it and the master will continually look for the slave. If a connection attempt fails, the master will wait for 2 seconds before reattempting a connection. This 2 second delay can be varied by issuing it an ATS530 command with an appropriate value in the range 100ms to 15000ms.
IMPORTANT NOTE: When S Register 507 = 0, the DSR input to the module MUST be asserted for the auto connection to succeed. When operating at TTL levels a 0V is seen as an assert state. When operating at RS232 levels and voltage greater than 3V is seen as assert. It is usual to connect the DTR line of the host to the DSR line of this device.
7.2 Audio Cable
With a pair of these modules it is possible to replace a mono audio cable with two way traffic. That is, a setup where a microphone is connected to a speaker at the remote end and vice versa. So this mode effectively replaces two audio cables.
Assuming the Bluetooth address of the master to be <bdaddr_m> and that of the slave to be <bdaddr_s>, the master module is configured by sending it the following AT commands.
AT&F
ATS512=1
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