The first time I bought some UART bluetooth devices, I ordered them on suntekstore.com website. Since these devices seems promising, i ordered a few more on DealExtreme for my job.
I discovered that even these boards seem identical, they had different firmwares.
The suntekstore ones has HC05 firmware, the DealExtreme ones has linvor 1.5 firmware.
The differences between them is mainly the AT command set.
Linvor 1.5 also known as HC06
This firmware offers a very limited set of AT command.
By default the baudrate is 9600 8N1.
For this firmware you have to not send LF or CR character at the end of your AT command.AT programming mode is up when your board is not paired by bluetooth devices. For this firmware, you have to copy/paste AT command since timings is important. You can send about one command per second.
And that's it !!! No other AT command.
In the next, post I will provide some links to the HC05 firmware. This one is a bit better than HC06.