BLUETOOTH WIFI MODULE SH-04 for Bluetooth turn serial

BLUETOOTH WIFI MODULE SH-04 for Bluetooth turn serial
The HR311A is a true one-port surface-acoustic-wave (SAW) resonator in a low-profile metal TO-39 case. It provides reliable, fundamental-mode, quartz frequency stabilization i.e. in transmitters or local oscillators operating at 311.000 MHz.
BLUETOOTH MODULE SH-04 for Bluetooth turn serial

Product Overview
SH-04 Bluetooth Serial core modules This design uses CSR's Bluetooth chips, V2.0 protocol standards, industry-standard 28mm x 15 mm x 2.35mm, the volume size of a compact, self-efficienton-board antenna, transparent serial port with a variety of Bluetooth adapter, paired Bluetooth mobile phone use, but also the use of a pair of master and slave.
SH-04-D Bluetooth serial module with a backplane, This design is a SH-04 module, coupled with external circuit based on the floor, the working voltage is from 3.3V to 5V, leads to TTL, and 232, matching the success of the signal LED pin, the host module also leads to re-search for new slaves pin (default master and slave memory matching addresses will be down, if the next time there are multiple simultaneous Bluetooth, the host will automatically find previously paired off from the machine, if the high electrical pulse to this pin is to give up memory).The software contains the factory default AT command set, as
detailed in point 6 of the instructions.

2. the circuit interface
RS232 serial port (TTL level), (also equipped with a floor-level serial port