Networking and Communication

To find and share information, the Macintosh computer can communicate with other computers in a number of ways. This section provides a brief overview of Macintosh networking and communication technologies, the most important of which are covered in much greater detail in Lesson 11, “Wireless Networking,” and Lesson 12, “Network Troubleshooting.”

Bluetooth

Mac OS X 10.2 integrates Bluetooth capabilities into the operating system but focuses on supporting only a few Bluetooth devices, such as cell phones and personal desktop assistants (PDAs). Mac OS X 10.3 has added support for a wide range of other Bluetooth devices, such as headsets, printers, and network access devices. Mac OS X 10.4 Tiger supports an even wider range of Bluetooth devices.

Bluetooth support is implemented in all Macintosh computers that have built-in USB and are running Mac OS X 10.2 or later. Many Macintosh desktop and portable models can be ordered with built-in Bluetooth capability, and Bluetooth functionality can be added inexpensively with third-party external USB devices.

Ethernet

All recent Macintosh computers come with built-in Ethernet ports that support 10Base-T at the minimum; newer models also support 100Base-T, and the high-end models even support the superfast Gigabit Ethernet standard.

Networks running 10Base-T, 100Base-T, and 1000Base-T Ethernet use Category 5e or Category 6 cables that contain several pairs of twisted wires. These categories define technical parameters of the cables and connectors; generally speaking, higher categories can handle higher speeds. The ends of cables used in 10Base-T and 100Base-T networks have RJ-45 connectors, which look similar to the RJ-11 connector on a telephone cable but are larger and wider. RJ-45 plugs (shown in front and side views in the following figure) have room for up to four pairs, or eight wires, whereas phone plugs have space for only four wires. Ethernet cables that support Gigabit Ethernet have all eight wires present, and are very high quality, in order to ensure reliable data transmission even at Gigabit Ethernet speeds.

Infrared

Using infrared technology, a computer and an external device (such as a printer, modem, or PDA) can communicate wirelessly over a short distance. Infrared Data Association (IrDA) is a collection of standards that cover various methods of using infrared light emission for communication.

IrDA is similar to Bluetooth in that it can be used to connect devices in a limited area. But because it communicates with infrared light waves rather than high-frequency radio waves, it requires an unobstructed line-of-sight path between the communicating devices. Wireless fidelity (Wi-Fi) networking based on the IEEE 802.11 standard such as the Apple AirPort is faster and more flexible than IrDA. IrDA is supported only on the iMac 233 MHz and PowerBook models through the PowerBook G4 (Gigabit Ethernet).

IrDA components are located in the /System/Library/Extensions folder, where they are available early in the startup process.

Infrared User Controls

If you are using a Mac OS X computer with an IrDA port, you can configure the port in Network preferences:

Ensure that the IrDA port is enabled, and then choose it from the Show pop-up menu if you want to configure the port for use as your network connection.

The IrDA icon in the menu bar can exhibit the following states:

Status Indicator	Meaning
	IrDA modem is idle.
	IrDA modem is looking for devices.
	IrDA modem is connected.
	IrDA connection was interrupted.
	No IrDA hardware is available.
	IrDA connection is off.

Modem

Computers process information in digital format, as strings of 1s and 0s. In contrast, normal phone lines are analog—they transmit data as a series of continuous waves. So a modem (modulator/demodulator) modulates outgoing data from digital to analog and demodulates incoming data from analog to digital.

All current and in-warranty Apple computers have internal modems that support either the V.90, V.92, or K56flex standards for 56 Kbit/s connections. An internal modem plugs into a phone jack using a standard phone cable with RJ-11 connectors on each end.

Modem connection speed varies depending on many factors. You'll find more information about troubleshooting modems in the Knowledge Base.

CUPS

With Common UNIX Printing System (CUPS), you can manage printer classes, printers, and print jobs through a web browser. Apple uses CUPS as its print spooler in Mac OS X. When you use Print Center to set up a printer, you are relying on CUPS for interaction with various printing services.

• CUPS uses several industry-standard protocols, including:

• Internet Printing Protocol (IPP)

• Line Printer Daemon (LPD)

• PostScript Printer Description (PPD)

• Server Message Block (SMB)

• AppSocket (JetDirect)

CUPS configuration files are located in the hidden path /private/etc/cups.

To access CUPS on your computer, open a web browser and type http:// localhost:631 in the browser's address field.

CUPS provides both System V and Berkeley Software Distribution (BSD) command-line printing services for PostScript and raster printers, using IPP.

AirPort

AirPort is the Apple implementation of Wi-Fi, the IEEE 802.11 wireless networking standard. AirPort is covered in detail in Lesson 11, “Wireless Networking.” All current and in-warranty Apple computers support either AirPort or AirPort Extreme, though not all are sold with the necessary card installed.