bluetooth is particularly well suited for connecting devices over short distances without cables. It doesn’t always work smoothly – but with these tips and background information you will become a blue tooth expert.
When it comes to short-range wireless connections, bluetooth is the standard of choice – and it’s not without reason that the corona-warn app also uses this technology. you can find bluetooth wireless modules in pcs, notebooks and tablets as well as in speakers, headphones, smartphones, fitness trackers, smart thermometers, mice and keyboards. This technology is so popular because it is so easy to connect. Actually. Because often enough problems occur. We offer you solutions.
1. What is behind a bluetooth connection??
bluetooth allows data to be transmitted over short distances by radio. this basically includes video, audio and voice. In the simplest case, two devices are connected to each other – for example, a bluetooth speaker and a smartphone. They represent a piconet (personal area network), in which a point-to-point connection exists. The devices identify themselves to each other via AMA (active member address). Generally, up to eight devices can be actively connected to each other. Then it is called a point-to-multipoint connection. Here one device acts as "master", any other as "slave". In addition, the devices in the piconet can also remain in passive mode. Here they are logged in but marked as "standby" or "parked" on the bluetooth network. Therefore they get the address PMA (passive member address). since it is an 8-bit address, theoretically up to 256 devices (2 to the power of 8) can remain in standby mode. If several piconets are combined, this is called a scatter network. Here at least one bluetooth device must be included together.
To connect two devices via bluetooth, you have to activate the function on all devices. The pairing process always starts from one device: on the smartphone, select the device from the list that appears under "settings ->" bluetooth" appears. Before the actual connection, the devices exchange a security code, which they either just confirm or enter on a device. Only then does the pairing process start.
2. How the transmission works?
Bluetooth uses the ISM band (industrial, scientific and medical band) in the range between 2.402 and 2.480 ghz. Here are 79 channels available, each 1 mhz wide. The frequency band around 2.4 ghz is also used by other wireless transmission methods – such as WLAN according to IEEE 802.11. This is why bluetooth uses frequency hopping (FHSS), changing channels up to 1600 times per second. the many hops and the small data packets make the bluetooth data transmission very stable.
Bluetooth 5.0 for PC, TV& retrofitting a laptop: USB adapters from 5 euro
3. What is the difference between bluetooth and WLAN??
Bluetooth uses two transmission methods: synchronous connection oriented (SCO) and asynchronous connectionless link (ACL). SCO is used to transmit voice, which is transmitted in fixed timeslots with a maximum data rate of 64 kbit/s. Per ACL, bluetooth transmits data and requires the transmitting device to have memory to do so. Unlike WLAN, bluetooth can handle both transmission methods. WLAN can only transmit asynchronously.
4. Where can I find the bluetooth function on my device??
Regardless of whether smartphones, tablets or pcs – before devices can be connected via bluetooth, the function must be activated on each device. on smartphones, bluetooth is usually found in the "settings", more rarely in the "network" submenu, as well as in the status bar, which you can show by swiping the display from top to bottom. you activate the function by tapping on the symbol.
5. How to determine the bluetooth version?
In mobile devices such as smartphones and tablets, the processor determines the bluetooth version, because one-chip systems (SOC – systemon-a-chip) are built in. If you want to know which bluetooth version your android device has, first download a system app like "aida64" or "CPU-Z" to your mobile device to find out the exact CPU designation. For example, at CPU-Z you will find the specification "qualcomm snapdragon 808 1.82 ghz" under the "SOC" tab. If you look for it on the manufacturer’s website, you will find the bluetooth version – in this case 4 – in the technical data of the processor.1.
Bluetooth classes and range
The bluetooth classes determine what distance and power the wireless connection supports.
Class 1: here the transmission is done with 100 milliwatt (mw). The maximum range is 100 meters in the open air. This is the most powerful bluetooth class. transmitters and receivers of this class are often found in notebooks and pcs.
Class 2: the maximum transmit power is 10 milliwatts (mw), which should be sufficient for a maximum distance of up to 50 meters. corresponding hardware is installed in pcs, laptops or usb-bluetooth-adapters.
Class 3: the lowest power class brings it to 1 milliwatt and a range of 10 meters in the open air. The performance class is found in portable devices such as MP3 players. the range achieved in practice depends not only on the transmission power, but also on factors like the sensitivity of the receiver or the design of the antennas. In addition, obstacles that can affect performance, such as walls or metal parts. you can reduce the radio signal to a few meters even if the class is powerful.
6. Why does the smartphone not recognize all bluetooth devices??
In addition to the bluetooth version and the built-in hardware, the operating system of the mobile device has the greatest influence on the range of functions of the wireless technology. because it determines the bluetooth capabilities of the module. The more standard-compliant the wireless technology is integrated into the operating system, the fewer difficulties there will be when connecting to other bluetooth devices. Some manufacturers, such as samsung, often modify significant parts of the stock android to increase compatibility with their own devices. The modifications can also have a negative effect on the bluetooth functionality. One possible consequence: certain devices are not recognized as bluetooth devices at all.
At the same time, the bluetooth profiles are integrated in the operating system and determine the capabilities with which the wireless module communicates. an outdated operating system can lead to connection problems, because the manufacturers integrate more profiles in operating system updates. If your smartphone or tablet does not recognize a bluetooth device, an operating system update can help.
7. Why does the pairing not work, although the device is recognized??
sometimes your smartphone or tablet shows the bluetooth device you want to connect to, but can’t pair with it. one cause is old bluetooth connections, which are managed in a list on most mobile devices up to android 5. They are always available so that pairing works immediately when the smartphone is in the vicinity of the already known bluetooth partner. If there are too many entries in the list, the current pairing often fails. This can be remedied by deleting old pairing entries. You can find previously paired devices listed in the settings under "bluetooth" and delete an entry by touching the settings icon next to the device and clicking "unpair". Once you have deleted all old entries, you can start the pairing process again with the current device.
Overview: the current bluetooth versions
Version 3.0: in the specification bluetooth 3.0+HS bluetooth and WLAN come together. The abbreviation HS stands for high speed. The version uses WLAN (more precisely 802.11b/a/g) to transfer larger amounts of data. The choice falls on WLAN, since the technology already exists and uses the same frequency range. If necessary, an ad hoc connection is established that only works between two devices.
Version from 4.0: with the versions bluetooth 4.0, 4.1 and 4.2 bluetooth gets the additions low energy (LE) or bluetooth smart. In both cases, the focus is on low power consumption in order to transfer small amounts of data at longer intervals. The maximum limit is 220 kbit/s. The power-saving function does not work for larger data volumes. At the same time, transmission in low-energy mode only works up to a maximum distance of 10 meters. If one of the two devices is further away, the connection is interrupted or requires more power. Theoretically, 50 and up to around 100 meters are possible. Bluetooth from version 4.0 is used in particular for smartphones, wearables and smartwatches. there are different logos: in bluetooth smart, the module corresponds to low energy, such as in activity trackers.
Bluetooth smart ready means that the device uses bluetooth 3.0 and also low energy – as in smartphones, for example.
Version 4.1: any device can serve as a peripheral or hub. For example, a smartwatch will receive data from a heart rate monitor. In addition, the connection control is newly regulated. This allows an interrupted connection to be re-established as soon as the devices are in wireless contact again. Thanks to ipv6 support, bluetooth 4.1 prepared for the internet of things (iot).
Version 4.2: this version of bluetooth improves battery life by allowing the controller to resolve the address. At the same time, response time increases thanks to adjusted data packet lengths. the gain in speed should especially benefit connections between smartphone and activity trackers. For this, bluetooth uses 4.2 when pairing, only algorithms that are classified as safe by the US standardization authority NIST (national institute of standards and technology).
With bluetooth 5, the transfer rate or range of bluetooth connections increases. However, these new features only apply to the bluetooth LE (BLE) mode, i.e. the short-range connection to low-power bluetooth devices such as smartwatches and fitness trackers. most other bluetooth devices, such as speakers and headphones, use bluetooth classic – nothing changes for them with bluetooth 5. This is why, for example, the dual-audio mode of current samsung smartphones has nothing to do with bluetooth 5.
The higher data rate of up to 2 mbit/s is intended to enable BLE devices to quickly transfer larger amounts of data, such as extensive firmware updates or more fitness data. Other devices, on the other hand, benefit from a greater range: with bluetooth 5, this can now be around 200 meters, but only at a maximum transfer rate of 125 kbit/s. For each bluetooth transmission, the partners can either only use the higher data rate or the improved range.
Bluetooth 5 is downward compatible with existing versions: bluetooth devices with older versions of the standard can therefore also be connected to new bluetooth 5 smartphones, such as the samsung galaxy S20, the one plus 8 or the iphone 11.
Especially smartphones and devices for the internet of things, such as sensors, benefit from bluetooth 5.1. The latest bluetooth version can show its strengths particularly in navigation, determining the position in space with an accuracy of ten centimeters.
The current highest version improves the transmission meanwhile multiple headphones from the same audio source. Furthermore the LC3-codec optimizes the audio transmission from hearing aids.
8. What to do if the connection keeps dropping out?
You have successfully connected two devices via bluetooth – for example a smartphone and a fitness tracker. In the course of the day, however, the pairing is lost again and again. the error can be caused by too many entries in the bluetooth list of the smartphone. delete entries that are no longer used – see question 7. Check the battery of the paired device. If the battery level is too low, connection interruptions will occur. apps like bluetooth auto connect often help with android smartphones. Devices that have already been paired can be automatically connected via the app and prioritized under the "devices" menu item. In addition, under "profiles" suitable profiles can be activated. To do this, the app for the bluetooth device can be started automatically as soon as the bluetooth connection is established.
9. How does the connection of wearables via app work??
Many devices such as fitness trackers and smartwatches require an app to establish the bluetooth connection. If you want to connect a smartwatch – such as the LG G watch R – to your phone, download the appropriate application to your phone – in this case "android wear" – and install it. in some cases you also need a WLAN connection to pair the devices for the first time. If you have enabled wifi on the smartphone, turn on the smartwatch. A list of devices that are recognized in the environment appears on your smartphone. Select the name of your clock. Usually, both the watch and the smartphone will display a pairing code. The number sequences should be identical. If this is the case, tap "OK" or set a check mark on the smartphone and the watch to start the pairing process.
10. Can a bluetooth version be updated??
It would be very practical to update the bluetooth-version from about 3.0 to 4.0 to be able to update. However, changes from one version to the next usually affect not only the supported profiles, but also the hardware module itself. Therefore an update per se is not possible. In the case of mobile devices, bluetooth updates are often integrated into new operating system versions. This benefits with the latest android at the same time bluetooth compatibility.
11. Your car radio does not recognize the cell phone. What brings remedy?
Some car radios or navigation systems do not recognize current smartphone models. A firmware update of the car radio usually solves the problem. At the same time, an update can bring further benefits, such as a more stable connection to the smartphone or better audio streaming. you can update the firmware with a bluetooth-enabled notebook – provided the bluetooth module supports FTP.
Every time you update the firmware of the car radio, the user data, bluetooth settings, connected phones and phonebook data will be deleted. check on the manufacturer’s website if the update fits to your radio model. Download the update file to the notebook. To install the new firmware, you must have a bluetooth connection to the radio. In addition, the radio must be switched on. before the update process, delete all devices from the bluetooth pairing list of the radio and check if the bluetooth and audio streaming functions are enabled. During the update process, no phone should be connected to the radio.
now establish a bluetooth connection between notebook and radio. To do this, go to "control panel ->" on your computer hardware and sound -> devices and printers" and click on "add device". Select the radio, and confirm pairing with "yes" on the radio. Now the radio shows that it is connected to the computer. Also windows confirms that the device is added. under "devices and printers" select the radio and terminate the connection first of all. the firmware update should not start until you initiate it on the radio and re-establish the bluetooth connection on the computer at the same time.
For data transfer, use a gratistool such as bluetooth file transfer . select "connect -> refresh" to display the radio. double click on the device name and then on the "update" folder. move the downloaded firmware file to the "update" folder. this will copy the file to the radio. do not press any buttons on the radio during the update process. Once the firmware has been updated, disconnect the radio from the computer and switch it off and on again.
12. simultaneous audio output to two devices does not work
you want to output music from your smartphone via bluetooth to a speaker and headphones at the same time. Although you can pair both peripheral devices with the phone, music playback will only work on one device at a time.
If the smartphone supports at least bluetooth 4.0, a simultaneous connection to two devices is possible. Because then the bluetooth module in the cell phone can handle the so-called dual mode. However, one of the connected devices must support bluetooth classic, i.e., the normal bluetooth mode. The other must be connected via bluetooth LE – and this standard is mainly used by small devices such as fitness trackers, but only a few headphones. Simultaneous audio output to two devices currently only works on samsung smartphones: since the galaxy S8 and S8+, there is a dual audio feature that allows this to happen. Conversely, a dual audio connection has been possible for some time: bluetooth headphones with multipoint function can be connected to two smartphones at the same time: you can then switch between the two audio sources on the headphones.
Common bluetooth profiles
Profiles are responsible for how and whether bluetooth communication works between devices. There are a variety of profiles, here are the most common:
A2DP: the "advanced audio distribution profile" transmits stereo audio signals.
AVCTP: "audio/video control transport" transmits audio and video data. It initiates and controls these.
AVRCP: the "audio video remote control profile" controls the remote control of audio and video devices.
BPP: the "basic printing" profile takes care of printing from your cell phone. Usually these are simple documents like e-mails.
BIP: use the profile "basic image" to transfer, display and print images in JPEG format.
GAVDP: the profile "generic AV distribution" controls the streaming of audio and video data.
HFP: with "hands free profile" the handsfree calling works.
HSP: the "headset profile" controls spoken input and output via headphones.
PBAP: the "phonebook access profile" allows the connected device to access the phonebook.
SYNC: the profile "synchronization" controls the synchronization of organizer data. Bluetooth devices can thus trigger the synchronization process by coming within the radio range of the pc.
windows and bluetooth: tips and solutions for everyday use
in the current operating system of microsoft windows 10, you will find the bluetooth settings under "settings -‘ devices -‘ bluetooth and other devices". there you can activate the bluetooth radio via a slide switch. Then switch on the device you want to connect to the PC and make sure it can be seen by the computer.
How you proceed differs depending on the device: with a loudspeaker, headphones or a mouse, you usually have to press a certain button for a longer time so that bluetooth is switched on and visibility is activated. Now click on "add bluetooth and other devices" in the windows settings and click on "bluetooth" for device type. Now the device should appear in the selection list, where you click on it and establish the connection with "ready". For some devices you have to authorize the connection with a PIN code. it is often 0000, otherwise you should find the appropriate code in the manual of the bluetooth device.
1. Windows does not find bluetooth hardware
Problem: you cannot activate bluetooth on the PC because the corresponding button is missing in the windows settings.
Solution: first, check in the device manager whether the bluetooth module is listed there. you must see a product name or a description like "bluetooth adapter" or "bluetooth radio" in the "bluetooth" menu. if this is not the case, restart the computer: often windows cannot activate bluetooth drivers after waking up from standby or hibernation mode, which is why the bluetooth hardware disappears from the device manager.
2. the bluetooth functionality cannot be activated
Problem: in the device-manager the bluetooth-hardware can be seen. However, the switch in the windows settings cannot be set to "on", but always jumps back to the off state.
Solution: go to the device manager and double click on the entry for the bluetooth hardware. select "update drivers" in the "drivers" menu and let windows automatically search for new driver software. If the operating system claims that the latest driver is already installed, go to the website of the PC or notebook manufacturer and search there for bluetooth drivers for your device. Take a look at the WLAN drivers offered, because many current notebooks have both wireless networks on one hardware module.
3. bluetooth hardware disappeared after windows update
Problem: after updating to windows 10 or a newer version of the system, for example the fall creators update, bluetooth will no longer work on your pc. no hardware is displayed under "bluetooth" in the device manager either.
Solution: if the installed driver does not support the update, windows 10 will not use it anymore. The bluetooth hardware therefore appears as an unknown device in the device manager. therefore check if you can find a corresponding entry in the device manager. if yes, you need to contact the PC manufacturer or the bluetooth hardware vendor to find an updated driver. Especially with a USB dongle, this can be difficult because you don’t have a manual for these external devices or you don’t know who the bluetooth adapter comes from at all. in this case the device manager can give you a hint: double click on the entry for the unknown device and go to the "details" menu. Select the entry "hardware-ids" under "property" and note the number sequence behind VID. You can search for it on this website, for example, which will then show you the manufacturer name hidden behind the VID, the vendor ID. You can then search for a current driver for the bluetooth device on the manufacturer’s support page.
4. usb-bluetooth-adapter is not recognized under windows
Problem: the bluetooth hardware does not show up in the device manager, but there is no unknown device listed there either.
Solution: the fault may not be in the bluetooth hardware itself, but in a device to which it is connected – for example, the USB controller. Therefore, change the view in the device manager by going to "view -‘ devices by connection". Now fan out all submenus, which are recognizable by the square bracket, until you see the bluetooth hardware displayed. now you can see to which internal interface the adapter is connected – usually it is a USB root hub or a PCI express root port.
if you see a yellow triangle with an exclamation mark on one of these devices, you should update the corresponding driver – usually it is the driver for the processor or chipset, which you can get from the PC manufacturer or from AMD or intel respectively.
5. dropouts during audio playback on bluetooth speakers
Problem: you have connected wireless speakers to the notebook via bluetooth. but from time to time there are disturbances during playback.
Solution: as with WLAN, interfering signals can affect bluetooth transmission. So first bring notebook and speaker closer together. If the playback is still faulty, you should check if you still have the bluetooth settings of windows open on the notebook. in this case, the notebook will continue to search for nearby bluetooth devices to connect to. But this activity can cause the dropouts in the audio output.
