Currently the form factor of this module is designed for the JR-style module bay. Many of the popular RC transmitters use the JR-style module bay: FrSky Taranis, FlySky Th9x, Turnigy 9X/R/Pro
The **ATmega-based board** has been designed to accept individual RF modules. This way you can select just the module or modules you want. The downside is that each module requires its own antenna. It can become cumbersome with 4 antennas protruding from the module. It is possible to soder the 4-in-1 module to the PCB using thin insulated wire. This 4-in-1 module requires only one antenna. Finally, the Atmega board has a 32KB flash memory. This is big enough to accommodate more than 15 protocols, but it cannot accommodate all the available protocols.
The **STM32-based** board has been designed to accept the 4-in-1 RF module with the antenna switcher (shown below). This means only one antenna. The STM32F103 processesor also has a much larger flash memory.
- CYRF6936 for DSM, DEVO, J6Pro ([here](http://www.trade4me.de/Devo-WK-21201RF-2-4GHZ-Telemetrie-Modul::34960.html), [here](http://www.walkeraonline.com/walkera-wk-devo-s-mod-devo-8-or-12-to-devo-8s-or-12s-upgrade-module.html), or [here](http://www.buychina.com/items/2-4g-module-cyrf6936-pa-lna-module-cyrf6936-20dbm-module-uuruunslkhi)
- [A7105](http://www.banggood.com/A7105-Wireless-RF-2_4GHz-Transceiver-Module-3_3V-Power-Supply-Module-p-909404.html) for Flysky, Hubsan
- [NRF24L01](http://www.banggood.com/2_4G-NRF24L01-PA-LNA-Wireless-Module-16+32mm-Without-Antenna-p-922601.html?utm_source=tradetracker&utm_medium=tradetracker_SE&utm_campaign=tradetracker&utm_content=227736) for Hisky, V2x2, CX-10, SYMAX and plenty other protocols
- The 4-in-1 RF module (available [here](http://www.banggood.com/DIY-2_4G-CC2500-NRF24L01-A7105-CYRF6936-Multi-RF-4-IN-1-Wireless-Module-p-1046308.html)) can also be connected with solder wires. To enable the antenna switcher the PE1 and PE2 pads must be soldered to ATmega pins, check the [schematic](#V23D_Schematic)
The schematic for the board is [here](#V23D_Schematic). Please note that is is the general schematic - there will be some minor differences (like solder jumpers) between this and the board.
1. The latest STM32 (32-bit) powered PCB V1.0t supporting the 4-in-1 RF module available from OSHPark [here](https://oshpark.com/shared_projects/GX51nEoH).
2. The 4-in-1 RF module is available [here](http://www.banggood.com/DIY-2_4G-CC2500-NRF24L01-A7105-CYRF6936-Multi-RF-4-IN-1-Wireless-Module-p-1046308.html)
1. A module case that fits your module like the one [here](https://www.xtremepowersystems.net/proddetail.php?prod=XPS-J1CASE) <br><imgsrc="https://www.xtremepowersystems.net/prodimages/j1case.jpg"width="200"height="180"/><br> or you can 3D print your own from a selection on Thingiverse ([Example 1](http://www.thingiverse.com/thing:1852868) [Example 2](http://www.thingiverse.com/thing:1661833)). <br> [<img src="http://thingiverse-production-new.s3.amazonaws.com/renders/55/1c/cb/0a/e4/5d2c2b06be7f3f6f8f0ab4638dd7c6fc_preview_featured.jpg" width="250" height="200" /> ](http://www.thingiverse.com/thing:1852868) <br> For 9XR/9XR Pro, a new 3D printed module is available which makes use of the built in antenna in the handle. This means nothing is getting out of the radio back! You can find all details of this module case on [Thingiverse](http://www.thingiverse.com/thing:2050717). <br><imgsrc="images/9XR_module.jpg"width="113"height="200"/><imgsrc="images/9XR_module_connector.jpg"width="274"height="200"/>
If you are only planning on using the PPM interface with transmitter you are ready to program the module as described in [Compiling and Programming](Compiling.md) the module.
If you have a transmitter that can support serial communication with the board then you need to solder some jumpers.
#### **ATmega V2.3d board**
There are four solder type jumpers on the bottom side of the board near the lower left corner when the bottom of the board is facing towards you. The silkscreen shows which jumper is which. These four jumpers enable the board to be configured in several ways as explaned below.
(J-2) Use (Jumper 2) to connect the incomming PPM signal to the RX pin on the processor
(J-3) Short (TELEM) only if you have done a telemetry mod to your radio, leave open if not needed. When connected, pin 2 of the two pin header (P3) is also connected.
**It is most likely J-2 will be the only one needing to be shorted for the serial method of sending model protocols. If you plan to use telemetry you will also need to solder J-3**