NEC DIRECTION L - SERVICE, Руководство по обслуживанию

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1-10 Technical Information
The two USB ports allow additional new plug and play serial devices without removing the
system cover. Simply plug the USB device into the port. The speed varies between
12 megabits per second (Mbps) for printers and 1.5 Mbps for mice and keyboards. Up to
127 USB devices can be connected to the computer.
The combination of the enhanced parallel port, buffered serial ports, and USB ports ensure
optimum performance for future peripheral devices and operating systems.
Sound System
The system board features Yamaha OPL
®
YMF715 audio chip. It integrates a 16-bit audio
codec, OPL3 FM synthesis and DAC, 3D enhanced stereo controller, and an interface for
MPU401 and a joystick. The chip also provides the following features.
„
Stereo analog-to-digital and digital-to-analog converters
„
Analog mixing, anti-aliasing, and reconstruction filters
„
Support for 16-bit address decode
„
ADPCM, A-law or
µ
law digital audio compression/decompression
„
Full digital control of all mixer and volume control functions
„
Sound Blaster
®
and Windows Sound System
™
compatibility
The system board provides connectors for the optional OPL4-ML wavetable synthesizer.
The OPL4-ML integrates the OPL3 audio system, general MIDI processor and wavetable
ROM. It provides FM synthesis and 24 distinct voices for music playback.
U.S. ROBOTICS MODEM BOARD (OPTIONAL)
Two modem boards are available: the U.S. Robotics
®
x2-capable Winmodem and the U.S.
Robotics x2-capable Sportster. Each modem board contains fax and modem capabilities.
The Winmodem provides fax and modem capabilities. The Sportster provides modem, fax,
full-duplex speakerphone, and voicemail capabilities. Each board provides receive transfer
rates of 56 Kbps (kilobytes per second) for data and 14.4 Kbps for fax.
DISKETTE DRIVE
The system comes standard with a 1.44-MB high-density diskette drive preinstalled in the
3 1/2-inch accessible device slot (drive A). The drive is connected to the system board via a
two-connector cable.