Most notebook computers and personal digital assistants (PDAs) have IR ports. Every major mobile phone brand has at least one IR-enabled handset, and even wristwatches are beginning to incorporate IR data ports. IR products for computer connectivity conform to the standards developed by the Infrared Data Association (IrDA).
The standard protocols include Serial Infrared (SIR) at 115 kbps, Fast Infrared (FIR) at 4 Mbps, and Very Fast Infrared (VFIR) at 16 Mbps. The complete IrDAprotocol suite contains the following mandatory protocols and optional protocols. Mandatory protocols:
- Infrared Physical Layer Specifies IR transmitter and receiver optical link, modulation and demodulation schemes, and frame formats.
- Infrared Link Access Protocol (IrLAP) Has responsibility for link initiation, device address discovery, address conflict resolution, and connection startup. It also ensures reliable data delivery and provides disconnection services.
- Infrared Link Management Protocol (IrLMP) Allows multiple software applications to operate independently and concurrently, sharing a single IrLAP session between a portable PC and network access device.
- Information Access Service (IAS) Used along with IrLMP and IrLAP, this protocol resolves queries and responses between a client and server to determine the services each device supports.
Optional protocols:
- Infrared Transport Protocol (IrTTP) or Tiny TP Has responsibility for data flow control and packet segmentation and reassembly.
- IrLAN Defines how a network connection is established over an IrDAlink.
- IrCOM Provides COM (serial and parallel) port emulation for legacy COM applications, printing, and modem devices.
- IrOBEX Provides object exchange services similar to the HyperText Transfer Protocol (HTTP) used to move information around the Web.
- IrDALite Provides methods of reducing the size of IrDAcode while maintaining compatibility with full implementations.
- IrTran-P Provides image exchange for digital image capture devices/cameras.
- IrMC Specifies how mobile telephony and communication devices can exchange information. This includes phonebook, calendar, and message data.
In addition, there is a protocol called IrDAControl that allows cordless peripherals such as keyboards, mice, game pads, joysticks, and pointing devices to interact with many types of intelligent host devices. Host devices include PCs, home appliances, game machines, and television/Web settop boxes.
An extension called Very Fast IR (VFIR) provides a maximum transfer rate of 16 Mbps, a fourfold increase in speed from the previous maximum data rate of 4 Mbps. The extension provides users with faster throughput without an increase in cost and is backward compatible with equipment employing the previous data rate.
The higher speed is intended to address the new demands of transferring large image files between digital cameras, scanners, and PCs. The IrDAhas developed a “point and pay” global wireless point-of-sale (POS) payment standard for hand-held devices, called Infrared Financial Messaging (IrFM). In an electronic wallet application, consumers use their IR-enabled PDAs to make purchases at the point of sale.
Users “beam” their financial information to pay for a purchase and receive a digital receipt. The IrFM protocol defines payment usage models, profiles, architecture, and protocol layers to enable hardware, software, and systems designers to develop IrFMcompliant products and ensure interoperability and compatibility globally. IrFM uses IrDA’s Object Exchange (OBEX) protocol to facilitate interoperability between devices.
The Infrared Data Association has formed a Special Interest Group (SIG) to produce a standard for interappliance MP3 data exchange using IR technology. The popularity of MP3-capable appliances begs for a standard connection between the MP3 players, computers, and the network, allowing consumers to easily move music from device to device without a cable or docking port.
The hand-held player should be able to transfer a song into a car stereo or home entertainment system. The MP3 SIG is identifying concerns specific to transferring MP3 data and building solutions into the protocol. Among the issues that must be addressed is how to identify copyrighted content and describe distribution restrictions to handle the MP3 content appropriately.
IR’s primary impact will take the form of benefits for mobile professional users. It enables simple point-and-shoot connectivity to standard networks, which streamlines users’ workflow and allows them to reap more of the productivity gains promised by portable computing. IrDAtechnology is supported in over 100 million electronic devices, including desktop, notebook, and palm PCs; printers; digital cameras; public phones/kiosks; cellular phones; pagers; PDAs; electronic books; electronic wallets; and other mobile devices.
When used on a LAN, IR technology also confers substantial benefits to network administrators. IR is easy to install and configure, requires no maintenance, and imposes no remote-access tracking hassles. It does not disrupt other network operations, and it provides data security. And because it makes connectivity so easy, it encourages the use of high-productivity network and groupware applications on portables, thus helping administrators amortize the costs of these packages across a larger user base.
