FAQs - Frequently Ask Questions

Out of 20 years in service and support, we collected the most frequently ask questions.

General questions

01 What is the advantage of an Evaluation Kit?

You can conduct radio tests and measurements prior to a costly design-in. It saves time and effort and contains everything required to get on air.

02 What are the advantages of choosing a module instead of doing a chip design myself?

The main reasons for using an RF module instead of doing a chip design is to reduce cost, time to market and risk. Both development cost (engineering and certification) and unit cost will be lower using an existing module up to a break even point. All modules are RED compliant and/or have FCC certification.

03 I want to design-in a radio module! What tools are required?

Besides your hardware design tools you would also need a software development environment (SDK). A signal analyser or sniffer might be of use.

Check out our homepage for documentation, hardware librarys, SDK, application notes and downloads.

04 What does the Development Sample Kit contain?

Three modules only for the purpose of evaluation. (Not to be confused with the Evaluation Kit.)

05 Where do I get the drivers for your USB products?

Please visit www.ftdichip.com/drivers/vcp for download and installation instructions. All our active USB products use this driver.

06 What PC software can I use to communicate with a module?

You could use our graphical configuration utility ACC for non-volatile parameter configuration and firwmareupdates. For access to the command and/or transparent mode you can use any terminal program such as Hterm or our SmartCommander.

07 Where do I obtain firmware updates?

The default source for firmware updates is our graphical configuration utility ACC, it has an integrated access to the firmware image server.

OTA updates (BLE, WLAN) are avialable throgh extra update packages through our support and the software downloads of the homepage.

08 Do all our radio modules include both a transparent and command mode operation?

No, the Tarvos-III and the Triton currently support the command mode only. (No transparent mode.) One of the next firmware releases will add that feature for this products, too.

09 What radio range can I reach with the module?

Please refer to the product specific documentation. There you will find ranges that can be achieved under the specified conditions. Part of the range depends on your end device hardware design (stable current supply, appropiate antenna and antenna path, housing, ground plane, …). Please use the range estimator avaialble in RED Expert ( https://www.we-online.de/redexpert/#/smodule/30).

Hardware Design

01 How do I design a good antenna?

There is no simple answer. Any conductor carrying alternating current acts like an antenna. "Good" antenna design requires expert knowledge and years of experience. The difficulty is to make it transfer the energy as efficient as possible into “free space”. The first consideration is about the product enclosure, if the antenna can be placed inside (plastic housing) or outside (metal housing). If outside, then it is best to buy a rugged antenna designed for external use. If inside, the antenna can be designed as part of the PCB, mounted on the PCB as a component, or made out of a piece of wire.

02 What should I consider when doing the schematic design?

Important: study the module datasheet and manual carefully, also take a look at the hw design librarys and evaluation board's manual for a reference design!

Make sure all ground pins are connected to the same ground net. The supply voltage should be stable and noise free. For high power modules, make sure the power supply is sufficient. If it is battery operated you may need to add super-caps. Pay attention to the I/O connections, for voltage level compatibility, pull-ups and floating pins. The Reset pin must be available for external reset, or controlled by host MCU. Do also add the possibility for in-circuit re-programming connector (just in case a firmware update is needed). For the antenna output it is a good advice to add a shunt and series component, providing the possibility for antenna matching.

03 What should I consider doing the PCB layout?

The most important is to use a ground plane where all ground pins are connected with as short as possible traces. For this reason the board must be designed with two layers at least. The ground plane will also be a part of the antenna, if using a PCB or built in antenna. Place any noisy devices (such as DC/DC switching regulators and displays) away from the RF module. The antenna connection should be as close as possible to the RF pin.


01 Which regulations are supported for Europe?

All modules destined for use in the European Union have RED certification as well as a declaration of conformity.

02 Which modules can be used in different countries?

2.4 GHz can be used almost all over the world. For other frequencies it depends very much on the respective national radio regulations.

03 Are the modules RoHS and REACH compliant?


01 What is Wireless M-Bus?

Wireless M-Bus is a European Norm for utility meter communication. It is standardized under the specification series EN13757 (-3 and -4), and is widely used for electricity, gas, water and heat cost allocators. Other environmental sensors are also supported. You are welcome to check YouTube for our Würth Elektronik group channel for webinars relating to this topic.

01 How do I manage to receive a radio package from my meter?

Please check the meter's documentation and configure your wireless M-BUS receiver accordingly. The mode selection table is described in our product manual.


01 Do we have traceability for all our modules?

All modules are traceable from manufacture and end control through to distribution to the end customer.


01 When can I use a mesh network?

Mesh networks are best suited for small amounts of control/monitoring data which is to be sent to or from a node in a mains operated network. Applications could be electricity meters or lights in a home automation system. Mesh networks use router nodes which retransmit messages, and therefore require considerably more energy.

Bluetooth / Bluetooth Low Energy

01 What do I need to know when using Bluetooth Technology in my Application?

The end device must also be Listed and Qualified with the BT SIG. This involves membership in the BT SiG and a listing fee for the BT SiG as well as performing the listing/qualification process as explained in the user manual of the modules (see chapter "Bluetooth SIG listing/qualification").

02 How do I create a BLE app for my smartphone (Android/iOS)?

Please follow the instructions in the documentation. See Proteus-I / Proteus-II App Notes ANR002 / ANR005 for further details.

03 What security features does BLE provide?

BLE uses pairing and bonding similar to classic BT. Data can be encrypted using AES128 as defined by the BT Specification. Our OTA firmware update uses ECC instead of AES encryption.

04 How do the central and peripheral roles differ from each other?

There are many differences between central and peripheral roles. Generally speaking however, central devices initiate pairing and connection and act as the master of a BLE connection, whereas peripheral role devices advertise their services and act as a slave.  


01 Does the Calypso handle Audio/Video streaming?

No, with it's included Firmware it is rather intended for IoT applications with low data rates. (Audio/Video would be defeating the aim of the "low power module"). For a Streaming Application a custom firmware is required.

02 How is encryption and authentication handled by the Calypso?

Calypso supports up to 6 parallel secure sockets for communication using the SSL and TLS protocols. SSL/TLS protocols provides features like end-to-end encryption and authentication to ensure secure communication between network peers.

WEP, WPA and WPA2 are also included in the module for the Wi-Fi encryption.

Further information:

For more information please contact wireless-sales@we-online.com or directly send an inquiry to our technical support.