Application Note Setting up the
Bluetooth Interface by Dieter Fauth Last revision of this document: 2006-12-14
Adaptus Bluetooth Imagers 1 Overview Last revision of this document: 2006-12-14
1 Overview This document describes certain aspects of the Bluetooth interface in Adaptus Imagers that are not covered by the users guide. Models: •
4820
•
3820
•
2020
1.1 Required knowledge The reader should have a generic knowledge about computers and technical devices. Some background about our barcode Imagers does help.
1.2 Revision History 2005.07.19 2005.07.20 2005.07.21 2005.07.27 2005.08.08 2006.12.14
First release Added BlueSoleil stack and scattered changes. Added Pocket PC devices Scattered changes Added chapter “Advanced” Changed the devices names to fit the current devices.
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Adaptus Bluetooth Imagers 1 Overview Last revision of this document: 2006-12-14
Contents: 1 Overview.................................................................................................................................................... 2 1.1 Required knowledge............................................................................................................................... 2 1.2 Revision History...................................................................................................................................... 2 2 Security...................................................................................................................................................... 2.1 Pairing..................................................................................................................................................... 2.2 Authentification....................................................................................................................................... 2.3 Security Discussion................................................................................................................................. 2.4 Discovery modes.................................................................................................................................... 2.5 Linking Scanner to Base.........................................................................................................................
4 4 4 7 7 7
3 Advanced Settings..................................................................................................................................... 8 3.1 Lock base for new Imagers..................................................................................................................... 8 4 Connecting to third party devices............................................................................................................... 9 4.1 Discovery modes.................................................................................................................................... 9 4.2 Pocket PC devices.................................................................................................................................. 9 4.2.1 Pocket PC 2003 with Widcomm stack................................................................................................. 9 4.2.2 Pocket PC 2003 with Drakar (Socket) stack (D9500 and D7900)...................................................... 12 4.3 USB dongles and regular PCs.............................................................................................................. 15 4.3.1 Win XP with the Microsoft BT stack................................................................................................... 15 4.3.2 Win XP with the WidComm stack...................................................................................................... 17 4.3.3 Win XP with the BlueSoleil stack....................................................................................................... 18 5 Troubleshooting....................................................................................................................................... 21 5.1 Linking with the base after experiments................................................................................................ 21 6 Adanced communication......................................................................................................................... 22 6.1 Access the Imager via the base............................................................................................................ 22 6.2 Access the Imager via any Bluetooth dongle........................................................................................ 22 7 FAQ......................................................................................................................................................... 23
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Adaptus Bluetooth Imagers 2 Security Last revision of this document: 2006-12-14
2 Security For all devices that can be accessed via an air connection, security is a major issue. Especially Bluetooth has been in the news recently for security issues. Our driver stack is supplied by a major player in the Bluetooth scene, a lot of effort went into securing the low level procedures. You as a user need to understand the settings that influences the security.
2.1 Pairing Bluetooth devices can support a feature called pairing, that means, these two devices will know each other and connect without further questions. In the default setting the pairing is optional. For a better security it is recommended to set Pairing to “required� (perhaps with encryption). Note:
It is important that you change the base first. Doing it the other way around, you will loose connection between the base and the Imager. If this happens by accident, then go back to the setting before the change, that re-establishes the connection.
COMMAND FOR BASE
SECURITY LEVEL
COMMAND FOR IMAGER
0 no security 1 no security
2 medium
3 fair
2.2 Authentification Each device can also be equipped with a passkey. The default passkey is 1234, so it is highly recommended to change it to a more secret one.
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Adaptus Bluetooth Imagers 2 Security Last revision of this document: 2006-12-14
You must enter the same passkey for both the base and the Imager: Scan the BASPIN barcode, then the characters of your PIN followed by the Save barcode. Do the same for the Imager, but start with the BT_PIN barcode. A maximum of 16 characters can be used for the passkey. Please note that a 4 digit numeric only PIN can be cracked in less than a second under certain circumstances. Therefore use at least 8 alphanumeric characters.
COMMAND FOR BASE
COMMAND FOR IMAGER
Programming Chart
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Adaptus Bluetooth Imagers 2 Security Last revision of this document: 2006-12-14
Programming Chart
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Adaptus Bluetooth Imagers 2 Security Last revision of this document: 2006-12-14
Note:
Be careful when you change the the passkey. If the devices are already paired, they do not check their passkeys immediately. This check happens on the next pairing.
Note:
With the freeware program KeePass (http://keepass.sourceforge.net) you can create and maintain secure passkeys.
2.3 Security Discussion The discussion about Bluetooth security is still ongoing. These are two interesting web sites: http://www.eng.tau.ac.il/~yash/shaked-wool-mobisys05/. http://blogs.fullthrottle.com/EmbeddedBlue/ In general the discussion is whether the passkey is save at all. The group that cracked the passkey used a 4 digits numeric only PIN for their experiments. They recorded the pairing process of two devices and used a brute force attack to crack the PIN. It clearly shows the a 4 digits PIN is not save at all. It will be cracked in 60 Milli Seconds on a regular PC. Even a 9 digits PIN can be cracked in less than 2 hours. With the 69 different characters that can be used in passkeys, we get a much better mileage. An 8 characters passkey needs 98 years to crack (if we need all the tries). If we assume the correct passkey will be found after 50% of the time, it is still 49 years. That is safe enough for most applications. Otherwise just add more characters. But keep in mind that dictionary lookups can crack simple word passkeys very fast as well. So choose a good passkey with scattered characters. Another security measure is to avoid pairing devices in public places. What they don't see, they cannot crack. The table below shows the calculation details. Characters in passkey Max tries with digits only Seconds to crack Minutes to crack Hours to crack
1 10
4 10000 0,06 0 0
5 6 7 8 100000 1,00E+06 1,00E+07 1,00E+08 0,6 6 60 600 0,01 0,1 1 10 0 0 0 0
Max tries with alphanumeric Times better than digits Seconds to crack Minutes to crack Hours to crack Days to crack Years to crack
69 2,27E+07 1,56E+09 6,9 2,27E+03 1,56E+04 136 9384,19 2,27 156,4 0 3 0 0 0 0
1,08E+11 1,08E+05 6,48E+05 1,08E+04 180 7 0
7,45E+12 7,45E+05 4,47E+07 7,45E+05 12.411 517 1,4
9 1,00E+09 6000 100 1,7
5,14E+14 3,55E+16 5,14E+06 3,55E+07 3,08E+09 2,13E+11 5,14E+07 3,55E+09 856.331 59.086.813 35.680 2.461.951 98 6.764
2.4 Discovery modes By default the Imager and the base are in a mode where they are not discoverable by other Bluetooth devices (The initial linking is not done via Bluetooth). See chapter 4.1 on page 9 for more details.
2.5 Linking Scanner to Base Please see the details about the link modes in the System Manual.
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Adaptus Bluetooth Imagers 3 Advanced Settings Last revision of this document: 2006-12-14
3 Advanced Settings 3.1 Lock base for new Imagers As soon as you place a new Imager into the base, it gets connected to the base. In general this is the best setting for most users. Sometimes it is a good idea to prevent new Imagers connecting to the base. This can be controlled by this setting. Note:
In case you need to replace a Imager, you must enable the automatic linking for this action.
COMMAND
COMMAND
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
4 Connecting to third party devices The Imagers can be connected to typical Bluetooth dongles and PDA type devices. In order to work that way, a few settings must be done. The passkey and pairing behavior is the same as with the base station, see chapters 2.1 and 2.2 for the configuration barcodes. All barcodes for the base station are not applicable here.
4.1 Discovery modes The Imagers are not discoverable by default because the 2020 base does find them without a Bluetooth connection. In order to connect with third party devices, the Imager must be visible.
COMMAND FOR IMAGER
COMMENTS The Imager is not discoverable by other Bluetooth devices. This mode is used together with the 2020 base. The Imager is discoverable by other Bluetooth devices. Use this if you use a third party BT dongle. The Imager is discoverable by other Bluetooth devices and it automatically reconnects when it comes back from the out of range situation. Requires a more complicated setup in the host! And with most stacks it won't work properly with current firmware.
4.2 Pocket PC devices For the PAD type devices we concentrate to the Windows CE based devices. The setup depends on the Bluetooth driver stack used in a particular PDA.
4.2.1 Pocket PC 2003 with Widcomm stack This stack was tested with an HP iPAQ 2210, Pocket PC 2003 (German Edition). The Bluetooth stack has Version 1.4.1 Build 60. This device stands for a lot of devices using the same driver stack . The screenshots are in German, but I bet you get the ideas anyway. Note:
In my tests I did not get the PIN to work, the iPAQ never asked for a PIN.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
Before you start, you might want to make sure the Imager is not paired and connected with another device. Scan the three barcodes below and also ensure you have a good passkey. See chapter 2.2 on page 4 how to do this.
First we want to check the Bluetooth settings to avoid surprises.
In the settings you need to select the tab for the Serial ports. Click the right arrow until it appears.
Here we see which port is assigned, in my case is outgoing assigned to COM8. Ensure the service is active and choose the security options to your needs.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
Now open the Bluetooth Manager.
There might be already some devices. In the screen shot there are no devices yet. Click on New, then Connect.
Select search for Bluetooth devices, then click next.
You can click on either of the marked buttons.
Now the Imager appears in the list. Mark it and click next.
After a few seconds it shows the service “Serial Port Server Port 1�, select it and click next.
If the Imager was not found, did you made it discoverable? See chapter 4.1 on page 9 for more details.
If it does not show the service, click back and try it again.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
For the tests I used the freeware tty.exe as a terminal program. Open COM8.
The Bluetooth Browser opens and let you select the device that shall be connected as COM8. Select the Imager, then click OK. Sometimes while the tests, the WidComm stack seamed to hang. This lasted for more than a Minute. Perhaps it searches for devices. Sometimes even a warm boot was required.
The Imager chirps to show that its connected, then you can scan a barcode and it appears on the screen.
4.2.2 Pocket PC 2003 with Drakar (Socket) stack (D9500 and D7900) Before you start, you might want to make sure the Imager is not paired and connected with another device. Scan the three barcodes below and also ensure you have a good passkey. See chapter 2.2 on page 4 how to do this.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
First we want to check the Bluetooth settings to avoid surprises.
Ensure your device has a name of your choice and setup the other setting according your needs.
If the Bluetooth icon is missing, you need to enable Bluetooth in the device settings (Radio Manager).
Here you can see which Com-Port gets used.
Now we start the search for devices.
Click OK.
This window shows the known devices, in my case it is empty. Click onto the Search icon (two eyes).
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Click Next.
Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
Ensure that “Any Bluetooth device� is checked, then click next.
This takes some time...
It found the Imager, check it and click next.
Enter the Passkey (PIN), click Reply.
If the Imager was not found, did you made it discoverable? See chapter 4.1 on page 9 for more details.
This takes some time...
Click Finish.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
4.3 USB dongles and regular PCs Since Bluetooth is a fairly new technology, there exist several options for the PC side. All have their specific issues. In general you have to be patient because some functions take more than a minute to complete.
4.3.1 Win XP with the Microsoft BT stack Starting with the service pack 2, there is a Bluetooth driver stack with Windows XP.
Before you start, you might want to make sure the Imager is not paired and connected with another device. Scan the three barcodes below and also ensure you have a good passkey. See chapter 2.2 on page 4 how to do this.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
To search for new devices, click the “Add...� button. Open the Bluetooth devices (can be found in the Taskbar). You might see some known devices.
After some time you see the Imager. Mark it and click next. If the Imager was not found, did you made it discoverable? See chapter 4.1 on page 9 for more details.
Now enter the passkey (default is 1234). See chapter 2.2 on page 4 for more details about the PIN.
Windows connects to the device...
Here you can see the used COMxx ports.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
You can also find a list of ports in the Bluetooth devices.
4.3.2 Win XP with the WidComm stack The screenshots below where taken with version 3.0.1.915 of the WidComm Stack. There are many different versions out, so your specific millage might vary.
Before you start, you might want to make sure the Imager is not paired and connected with another device. Scan the three barcodes below and also ensure you have a good passkey. See chapter 2.2 on page 4 how to do this.
Click on “View devices in range” in the left area. The Imager appears with a question mark. No double click onto it. If the Imager was not found, did you made it discoverable? See chapter 4.1 on page 9 for more details. Open “My Bluetooth places”.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
It might take some time until the icon changes to this connector view. Double click onto the connector icon or right click and select “Connect to Bluetooth Serial Port�.
This takes some time,
No the Icon changes again to show that we are connected.
Right click and select properties to see the dialog below.
4.3.3 Win XP with the BlueSoleil stack The BlueSoleil stack claims to be the most user friendly Bluetooth stack. You can easily test that by downloading it from their web site (http://www.bluesoleil.com). The stack runs in demo mode (5MB max transfer). The resulting virtual ComPorts (SerialPorts) are not visible by all programs. It uses a deprecated method to register with the operating system1. With the exception of the outdated method, the stack works nice and reliable. The tested version is V1.6.1.4 Release 050606, Stack Version 05.04.05.20050408.
Before you start, you might want to make sure the Imager is not paired and connected with another device. Scan the three barcodes below and also ensure you have a good passkey. See chapter 2.2 on page 4 how to do this.
1
Users of the terminal program YAT3 should update to V3.1.0.107. Page 18 of 23
Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
If the Imager is not listed yet, then start a search.
Open the BlueSoleil Window. Caution: In the task bar there might be two Bluetooth icons, one for the BlueSoleil (dark blue) and one for the MS Stack (light blue).
Double click onto the Imagers Icon, then enter the passkey. See chapter 2.2 on page 4 for more details about the passkey.
Now the Imager appears in the “orbit�. If the Imager was not found, did you made it discoverable? See chapter 4.1 on page 9 for more details.
Right click onto the Imagers Icon, select SerialPort A or B.
Now the icon of the SerialPorts changes to yellow.
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Adaptus Bluetooth Imagers 4 Connecting to third party devices Last revision of this document: 2006-12-14
The icon of the SerialPorts changes to green. Find the assigned port in the status. (right click)
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Adaptus Bluetooth Imagers 5 Troubleshooting Last revision of this document: 2006-12-14
5 Troubleshooting Sometimes the Bluetooth stacks seam to hang. If it does not recover after a few minutes, try restarting your PC or PDA. Try a warm boot first on a PDA. In case of the Widcomm stack a hanger appeared after changing the passkey of the Imager. It seams there is a problem with the stack. This could be duplicated with other devices as well, so it is not the Imagers fault. Below is a barcode that resets the Imager in case you want to do that.
To remove any traces of a connected device from the Imager, scan the barcode below.
Set the Imager to factory defaults.
5.1 Linking with the base after experiments If you experimented with third party devices, and then want to link with the base again, you will like this section. It contains all steps to achieve this. The following steps assume you did not change anything in the base meanwhile.
COMMAND
COMMENTS Sets the Imager to work with the base.
Ensure it is not linked to another device.
If the above does not help, did you lock the base? See page 8 for details. If the above does not help, try the factory defaults barcode.
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Adaptus Bluetooth Imagers 6 Adanced communication Last revision of this document: 2006-12-14
6 Adanced communication This chapter explains some details about the serial communication and how to communicate with the Imager.
6.1 Access the Imager via the base The Bluetooth Imagers use the same command set as its wired brothers. However you need a way to address a specific Imager connected to the base. This is done with a prefix to the command. Wired command [SYN]M[CR]COMMAND
Wireless command [SYN]M[CR]:NAME:COMMAND
The NAME can be an '*' if you want to talk to all linked images at once (nice if you only have one Imager). See more details in the system manual, chapter 10: Serial Programming Commands.
6.2 Access the Imager via any Bluetooth dongle This is a simple case, the command sequences are exactly the same as for a wired Imager. See more details in the system manual, chapter 10: Serial Programming Commands.
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Adaptus Bluetooth Imagers 7 FAQ Last revision of this document: 2006-12-14
7 FAQ What is Bluetooth pairing? Pairing is a special process used when two devices connect for the first time. The pairing process is used to generate a link key that is used for authentication purposes during subsequent Bluetooth connections between the two devices. What is Bluetooth bonding? This is a synonym for pairing. What is the difference between a passkey and a PIN? Well, actually they are synonyms to each other for most Bluetooth devices. A PIN usually means digits only, but good devices can use alphanumerics for a much better security. Third party device: Every time when my device went out of the receive range, I have to reconnect manually. Bluetooth is not designed for automatic reconnection. This has to be handled on application level. Unfortunately that means involving the user for most driver stacks. Third party device: What kind of connection do I get? The Imagers offer a serial port emulation. The Imager and the base do not find each other when I place the Imager into the base. Did you link the Imager to a third party device? Then it is probably setup that way. Scan the barcode BT_DNG0. In chapter 4.1 on page 9. Did you change the passkey on any side? The passkey must be the same for both devices. How can I create secure passkeys? With the freeware program KeePass (http://keepass.sourceforge.net) you can create and maintain secure passkeys.
What is the maximum data rate of Bluetooth technology? An asymmetric data rate (one way) of 721Kb/s (while permitting 57.6Kb/s in the return direction); and symmetric rate of 432.6Kb/s is possible according to Bluetooth spec. Where can I find more information on Bluetooth? There are many website. Just to name a few: www.bluetooth.com www.bluetoothcentral.com www.pocketpcfaq.com www.broadcom.com www.bluejackq.com bluesniff.shmoo.com
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