All our audio devices do not necessarily have the bluetooth, either a Hi-Fi, TVs, headphones, mp3 player, etc… For a computer, it is relatively easy to give a bluetooth connectivity, simply adding a USB bluetooth dongle or changing a room inside. But for a TV or a helmet, it is impossible to do this. Fortunately for us, there is a way to add bluetooth to our audio devices that are free without changing model of devices. To do this, simply get a transmitter or bluetooth receiver (depending on your use). On the other hand, unlike the dongles on pc that can transmit data, here, this will be only the audio. One of the models available on the market of the Bluetooth transmitter/receiver is BR – T7 of bottom bar, which has the advantage of being 2 in 1, unlike many models or 2 functions are separated into 2 modules, this allows in a single unit to be receiver or transmitter bluetooth! 
The characteristics
- Bluetooth transmitter
- Bluetooth receiver
- 8 devices paired memory
- Built-in battery
The test
The first thing to say is that it's small enough! I thought that it would be a little bigger, but it does just barely 5 cm x 2.5 cm! and very light. 
A microUSB cable is supplied for charging, as well as duplicate a mini jack male to 3.5 mm 3.5. This small device is a 2 in 1 function: it can be either a transmitter or a receiver. Therefore its use is especially useful in or there are one of the 2 devices you want to link in Bluetooth and therefore the other not. The switch is present on the right edge of the mini-appareil and is used when the unit is off. RX: TX receive Mode: Mode transmission the transmitter/receiver bluetooth can be used in wired or on battery power. Depending on the mode, the autonomy varies:
- transmission mode: 8 hours
- receive mode: 6 hours
A single button for ignition, shutdown, pause/play implementation and synchronization between devices. The bluetooth version is version 3.0, and the range is the 10 m classic. It supports A2DP and AVRCP profiles. At the level of use, no worries met: pairing is done quickly and the sound is quite correct!
Conclusion
Ideal when you have an audio input/output device in Bluetooth, and another without bluetooth, but you want to bind the 2 in wireless via bluetooth! As is 2 in 1, it has the advantage that one should not buy a set of receiver and transmitter. Thanks to its small size, it lies easily and can very easily be put in a pocket. In addition, a battery is integrated and allows an autonomy of approximately 6-8 h according to mode, which is not bad at all in view of its size! The product link: http://www.amazon.fr/gp/product/B0119DAPVA/ 