BT Rs232 Transceiver without adapter PCB

Hi, ive just bought following Bluetooth module(sorry, for the item being in German, but i guess it’s gotta be identical to all those cheap BT modules).

Now i have seen that most of them are on another adapter pcb which provides all the output pins and has some caps and a transistor i guess.

my problem is that i connected the module to my arduino UNO (3.3V), i can discover it using my PC and pairing works but the arduino doesn’t receive any serial data (no RX/TX leds blinking).
do i have to have the adapter board? is it only there to convert voltage if i connect it to 5V?

the pinout configuration i used is following:

i simply connected 3.3V, GND to arduino, then Rx to Tx and Tx to Rx. Is there anything else i have to do?