OBEX
Encyclopedia
OBEX is a communications protocol that facilitates the exchange of binary objects between devices. It is maintained by the Infrared Data Association
but has also been adopted by the Bluetooth Special Interest Group
and the SyncML
wing of the Open Mobile Alliance
(OMA). One of OBEX's earliest popular applications was in the Palm III personal digital assistant
. This PDA and its many successors use OBEX to exchange business cards, data, even applications.
Although OBEX was initially designed for infrared, it has now been adopted by Bluetooth
, and is also used over RS232, USB, WAP
, and in devices such as Livescribe
smartpens.
Currently supported on Android devices in 2.1.
Infrared Data Association
The Infrared Data Association defines physical specifications communications protocol standards for the short-range exchange of data over infrared light, for uses such as personal area networks ....
but has also been adopted by the Bluetooth Special Interest Group
Bluetooth Special Interest Group
The Bluetooth Special Interest Group is the body that oversees the development of Bluetooth standards and the licensing of the Bluetooth technologies and trademarks to manufacturers. The SIG is a privately held, not-for-profit trade association founded in September 1998. The SIG is headquartered...
and the SyncML
SyncML
SyncML is the former name for a platform-independent information synchronization standard. The project is currently referred to as Open Mobile Alliance Data Synchronization and Device Management...
wing of the Open Mobile Alliance
Open Mobile Alliance
The Open Mobile Alliance is a standards body which develops open standards for the mobile phone industry.- Principles :Mission: To provide interoperable service enablers working across countries, operators and mobile terminals....
(OMA). One of OBEX's earliest popular applications was in the Palm III personal digital assistant
Personal digital assistant
A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...
. This PDA and its many successors use OBEX to exchange business cards, data, even applications.
Although OBEX was initially designed for infrared, it has now been adopted by Bluetooth
Bluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
, and is also used over RS232, USB, WAP
Wireless Application Protocol
Wireless Application Protocol is a technical standard for accessing information over a mobile wireless network.A WAP browser is a web browser for mobile devices such as mobile phones that uses the protocol.Before the introduction of WAP, mobile service providers had limited opportunities to offer...
, and in devices such as Livescribe
Livescribe
The Livescribe paper-based computing platform consists of a digital pen, digital paper, software applications, and developer tools.Central to the Livescribe platform is the smartpen, a ballpoint pen with an embedded computer and digital audio recorder...
smartpens.
Comparison to HTTP
OBEX is similar in design and function to HTTP in providing the client with a reliable transport for connecting to a server and may then request or provide objects. But OBEX differs in many important respects:- HTTP is normally layered above a TCP/IP link. OBEX is commonly implemented on an IrLAP/IrLMP/Tiny TP stack on an IrDAIRDAIRDA may refer to:* Infrared Data Association, in information and communications technology , a standard for communication between devices over short distances using infrared signals...
device. In BluetoothBluetoothBluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
, OBEX is implemented on a BasebandBasebandIn telecommunications and signal processing, baseband is an adjective that describes signals and systems whose range of frequencies is measured from close to 0 hertz to a cut-off frequency, a maximum bandwidth or highest signal frequency; it is sometimes used as a noun for a band of frequencies...
/ACL/L2CAP/RFCOMM stack. Other such "bindings" of OBEX are possible. - HTTP uses human-readable text, but OBEX uses binary-formatted type-length-value triplets named "Headers" to exchange information about a request or an object. These are much easier to parse by resource-limited devices.
- HTTP transactions are inherently stateless; generally a HTTP client opens a connection, makes a single request, receives its response, and either closes the connection or makes other unrelated requestsHTTP persistent connectionHTTP persistent connection, also called HTTP keep-alive, or HTTP connection reuse, is the idea of using the same TCP connection to send and receive multiple HTTP requests/responses, as opposed to opening a new connection for every single request/response pair.- Operation :Under HTTP 1.0, there is...
. In OBEX, a single transport connection may bear many related operations. In fact, recent additions to the OBEX specification allow an abruptly closed transaction to be resumed with all state information intact.
Profiles
OBEX is the foundation for many higher-layer "profiles":| Classification | Profile |
|---|---|
| IrDA | Point and Shoot profile |
| Infrared Financial Messaging (IrFM) IrFM Infrared Financial Messaging is a wireless payment standard developed by the Infrared Data Association.-External links:**... profile |
|
| Bluetooth SIG | Generic Object Exchange Profile |
| Object Push Profile (phone to phone transfers) | |
| File Transfer Profile (phone to PC transfers) | |
| Synchronization Profile | |
| Basic Imaging Profile | |
| Basic Printing Profile | |
| OMA | SyncML SyncML SyncML is the former name for a platform-independent information synchronization standard. The project is currently referred to as Open Mobile Alliance Data Synchronization and Device Management... binding |
Supported devices
- All PalmPalm (PDA)Palm handhelds were Personal Digital Assistants which ran the Palm OS. Palm devices have evolved from handhelds to smartphones which run Palm OS, WebOS, and Windows Mobile...
s since Palm IIIPalm IIIThe Palm III was a personal digital assistant made by the Palm Computing division of 3Com. It went on sale in 1998 as a replacement for the PalmPilot handheld. It was the first Palm handheld to support infrared file transfer and a Flash ROM-capable operating system...
, except the Palm Pre, Palm Pre Plus, Palm Pixi and Palm Pixi Plus. - Most SharpSharp Corporationis a Japanese multinational corporation that designs and manufactures electronic products. Headquartered in Abeno-ku, Osaka, Japan, Sharp employs more than 55,580 people worldwide as of June 2011. The company was founded in September 1912 and takes its name from one of its founder's first...
, MotorolaMotorolaMotorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
, SamsungSamsungThe Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...
, Sony EricssonSony EricssonSony Ericsson Mobile Communications AB is a joint venture established on October 1, 2001 by the Japanese consumer electronics company Sony Corporation and the Swedish telecommunications company Ericsson to manufacture mobile phones....
, HTC and NokiaNokiaNokia Corporation is a Finnish multinational communications corporation that is headquartered in Keilaniemi, Espoo, a city neighbouring Finland's capital Helsinki...
phones with infraredInfraredInfrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
or BluetoothBluetoothBluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
port - Many other PDAs since 2003
- Many other phones with infraredInfraredInfrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
or BluetoothBluetoothBluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
port
Currently supported on Android devices in 2.1.
External links
- OBEX specification at IrDA.org
- OpenOBEX an open source implementation of the OBEX protocol