Technical information

CHAPTER 3
Devices and Ports
Sound System 57
CardBus Sound Input 3
The CardBus socket has a pin (SPKR_OUT) that carries a one-bit digital sound
signal output from the PC Card and input to the computer’s sound system. The
one-bit digital signal from the sound output pin is routed to the Screamer IC,
which in turn sends it to the built-in speaker and the external sound output
jack.
Sound Outputs 3
The sound system sends computer-generated sounds or sounds from an
expansion-bay device or CardBus card to the built-in speakers and the external
sound output jack.
External Sound Output 3
The sound output jack is located on the back of the computer at the left corner.
The sound output jack provides enough current to drive a pair of
low-impedance headphones. The sound output jack has the following electrical
characteristics:
■ output impedance: 33 ohms
■ minimum recommended load impedance: 65 ohms
■ maximum level: 1.17 V rms (3.3 V P-P)
■ maximum current: 18 ma rms (25 mA peak)
Internal Speakers 3
The computer has two 28mm speakers located between the keyboard and the
display. The computer turns off the sound signals to the speakers when an
external device is connected to the sound output jack and during power cycling.