Can Laird modules be used in a hostless cable replacement mode?

Answer

A pair of modules can be used in a hostless cable replacement mode using certain commands. On power up the master module will attempt to connect to the slave with the Bluetooth address set with the at+btr command. Effectively this means that whenever the two modules are within range of each other a connection will be made. The connection can be dropped/broken on deasserting the module's DSR line to allow the module to return to command mode. Note that the DSR input to the module must be asserted for the auto connection to work.

The following commands are used:

Master

Command Notes

at&f* Clear non volatile memory

ats512=1 Power state open and detectable

ats504=1 Suppress messages

ats507=2 Drop on de-assert of DSR

ats530=2000 Reconnect delay ms

at&w Save settings

at+btr Set peer address

Slave

at&f* Clear non volatile memory

ats512=4 Connectable and discoverable

ats0=-1 Auto answer, no response

at&w Save settings

Upon power cycling the modules, the master will attempt to connect to the specified slave. Once connected, data going into the UART of one module will be output on the UART of the other module.

Please see the manual for more details of the commands used.