Apple Desktop Computer manual Infrared Communication Link, Sound System

C H A P T E R 3

Devices and Ports

Table 3-2	Display resolutions and pixel depths
		Pixel depth	Pixel depth
Resolution	Vertical rate	(2 MB SGRAM)	(4 or 6 MB SGRAM)
640 by 480	117.233 Hz	32 bits	32 bits
800 by 600	94.97 Hz	32 bits	32 bits
1024 by 768	75.03 Hz	16 bits	32 bits

Infrared Communication Link

The iMac computer has a direct infrared (IR) communication link connected internally to serial port B. When the computer is placed within range of another device with an IR interface, it can send and receive serial data using the IrDA protocol. The other device can be an IrDA-equipped Macintosh PowerBook or some other device that complies with the Infrared Data Association (IrDA) standard. The minimum range of the IR link is approximately 2 inches, and the maximum range is 1 meter.

The IR link in the iMac computer supports IrDA at up to 4.0 Mbps. The IrDA modulation method complies with the IrDA physical layer standard, which can be found at ftp://irda.org.

Sound System

The 16-bit stereo audio circuitry provides high-quality sound input and output through the built-in microphone and speakers. The user can also connect external input and output devices by way of the sound input and output jacks.

The sound system is based on the Burgundy codec IC along with input and output amplifiers and signal conditioners. The sound system supports sample sizes up to 16 bits at a sample rate of 44.1 kHz.

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