Bluetooth Primer

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About Bluetooth®

Radio Technology to Replace Wires

Bluetooth is a wireless technology standard that uses radio frequencies to transmit information between Bluetooth- enabled connected devices. By embedding a Bluetooth chip and receiver into products, cables that would normally carry the communication signal can be eliminated. Beyond pure cable replacement, Bluetooth wireless technology also defines how devices interoperate and exchange information, effectively adding intelligence and new functionality to enhance the way people experience connectivity.

Bluetooth is well known as a "personal area network" wireless solution and is most commonly used to connect personal devices like the Pentax PocketJet printer to computing devices. Also known in this Radio Technology arena is WiFi (sometimes known as by its standard number, 802.11). WiFi is most commonly used in a networking environment where users would share common devices such as network printers.

Pentax chose Bluetooth as the preferred wireless connection for the Pentax PocketJet Printers because of the unique applications for personal printers in the mobile environment.

"Profiles" - The Wireless Language of Bluetooth Devices

Bluetooth supports a far-reaching range of devices; examples include, but are not limited to, printers, headsets, handhelds, mouse and other "Personal Area Network" devices. Because of the different kinds of data that devices can send as well as the error checking capability needed to transfer files in two directions (send and receive), the Bluetooth Organization has developed "Profiles" that are structured to the type of device or the required results from the device when sending and receiving communication.

The PocketJet printers utilize Serial Port Profile (SPP). SPP supports the widest range of computer devices and is a generic means for moving data between many types of devices. SPP must be chosen when configuring a PocketJet 3/3 Plus printer to a Bluetooth enabled computing device.

Power and Distance

Class determines the distance range, and therefore power, that a Bluetooth device has. The Bluetooth Organization describes three such "class" ranges (Class I, II and III). Class I is has the greatest distance potential. Under ideal conditions Class I has a reach of 100 meters (about 300 feet). Pentax PocketJet printers support Class I. However, the shortest power Class of any two devices will determine the useful distance for the pair. If the computing device supports Class II, the rated maximum distance to the printer becomes Class II and not Class I.

Class II devices have a rated distance of 10 meters (about 30 feet) and Class III devices are rated at 1 meter (about 3 feet).

The "Power" or "strength" of the signal of a radio-based device can be based on the reception of the antenna within the device. It is important to know that a Bluetooth antenna is somewhat directional - it transmits and receives more efficiently in some orientations than others, much like turning a portable AM radio around will effect its reception. And like an AM radio, the further the station is away from the listener, the more important orientation will become to clear reception. As you attempt to stretch the distance between your computer and your PocketJet3 printer, you will find that the orientation of both devices will affect the distance at which data transfer is possible. The software that comes with many desktop and notebook computers includes a visual "meter" that shows the approximate signal strength of the Bluetooth connection. If available, you can use this tool to get a feel for the best orientation of both your printer and computer if greater distances are important in the way you user your printer.

Signal Strength and Stationary Mounting

Radio reception can be hindered by steel in walls and a host of other obstacles. Bluetooth reception is no different, and maximum range is always a function of what lies between your computer and printer. This is especially true in certain mobile installations where the PocketJet3/3Plus is not only located inside a vehicle, but may be surrounded by a grounded metal mounting bracket whose orientation cannot be changed by the user. This type of installation can inhibit the ability to move the signal between the inside and outside of the vehicle to some extent. In particular, the design of the mounting bracket and how it does or does not envelop the printer will determine the strength of the signal in different directions.

The location of the PocketJet3 printer Bluetooth antenna is indicated in the diagram below, along with a relative indication of the strength of the signal that can be expected in a particular direction. When working at the limits of the range of the printer, especially when the printer is installed such that it cannot be rotated for best signal, this diagram may be of help in making the best mounting choice. For short-range communications, this will not prove to be an important issue and any orientation of the printer's and computer's antenna will work well. The PocketJet3 antenna is located in the right side of the top cover as shown. Longer arrows indicate stronger signals.

Important Bluetooth Buzzwords
"Discovery", "Connection", "Pairing", "Bonding" and "PIN Passwords"

Bluetooth requires that several processes such as discovery, connect, and pairing take place in order for two devices to connect for the first time. The connection may be set up as 'one time' events, or may be set up as connections that are remembered so as to make future connections simpler and quicker. The Pentax PocketJet3/ 3Plus printer with Bluetooth will accommodate both types of connections. Note that these processes determine only who may access a device, and does not necessarily determine the security of the data moving between devices. That issue is covered in the Security section which follows.

Discovery is the process of "discovering" what powered on, discoverable Bluetooth devices are within the Bluetooth range The Bluetooth software on your computer will have a function that looks for all discoverable Bluetooth devices and report them to you so that you may choose to connect to them. The Bluetooth specification doesn't require it, but most software will display a printer icon for the PocketJet3 because it announces to your computer that it is a printing device. Most devices, including the PocketJet 3/3Plus printer, are "discoverable" devices, however, a few Bluetooth devices may be configured to be "undiscoverable", Undiscoverable devices need to be configured to your computer with specific information about such a device.

Once a device is discovered, you may then choose to connect to it. This connection will either be a simple "unsecured" connection (direct, immediate connect) or "secured" connection which will require a password. The choice of "unsecured or "secured" will be a function of the software being used. As shipped from Pentax, the PocketJet3 allows for either connection.

In the case of a "secured connection", pairing must occur between the devices. To pair, a PIN password is used that in turn creates a more secure password between the devices. To pair to the Pentax PocketJet3/3Plus as shipped, you will need to tell your computer to pair with the PocketJet3/3Plus with the PIN password 'default'. Again, as shipped, the PocketJet3/3Plus does not require a password, but if your software insists on supplying one, it must be "default".

The PocketJet3/3Plus comes with a Windows-based Configuration Utility that allows you to change the PocketJet3/3Plus PIN password from "default" to a password of your choice. This password can be up to 16 alphanumeric characters. Changing the "PIN Password" ensures that only the person who knows the password can connect to the printer.

Bonding is when the computer's software remembers the first PIN paired connection. When a device is bonded it will not be necessary to enter any information (PIN/password) in order for the secure connection to take place.

The Pentax PocketJet 3/3Plus printer, as shipped, does not require pairing. If your device requires a pairing or PIN code for connection, the printer is set to accept "default" in the event that you change your PocketJet3 PIN password with the Windows configuration utility (provided by Pentax), pairing is no longer optional, and new PIN password MUST be supplied by your computer in order to communicate with the printer. The configuration utility also allows for turning this feature off again. This configuration utility can be found on the driver CD 3.3 and higher as well as here on the web.

Security

As shipped, the PocketJet3 can be discovered and connected without a pairing PIN password, and the data between your computer and printer is not encrypted. Using the "default" password will not automatically enable encryption and it would be possible that someone with special technical ability could intercept the data that you are printing.

A secure encrypted connection can only be set manually by using the Windows configuration utility and resetting the PIN password even if you simply set it to the same value of default when enabling this feature). Once a secure encrypted connection is set, the data that moves between your computer and the PocketJet3/3Plus will be encrypted using a 56-bit key.

The Windows configuration utility can be found on the driver CD 3.3 and higher as well as here on the web.

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