D-cache

(dee cache) abbr. See cache, data.

D-type connector

n. A connector often found in embedded and desktop systems. When viewed from the pins, the connector looks much like the letter D . The most common D-type connectors are

• 9-pin serial cables for RS-232 communications,

• 15-pin video cables for monitors and LCD projectors, and

• 25-pin parallel cables for printer connections or, in very old systems, RS-232.

D/A

(D-to-A) abbr. See D/A converter.

D/A converter

n. A hardware device that takes a set of bits, typically from a processor, as input and produces an analog signal proportional to the digital input as output. Short for digital-to-analog converter. D/A converters might be as simple as an array of resistors configured in the typical R-2R fashion or a hybrid module that generates very precise results with many bits of resolution. A simple use is to vary the intensity of a lamp (another approach that avoids the messy analog world is a pulse-width modulator that uses different switching rates and pulse lengths to control intensity).

D/A converter, multiplying

n. A peripheral device that converts a digital word to an analog voltage using a reference voltage to scale the result. Many D/A converters use a precisely regulated reference voltage as the basis for the analog out. In some, the reference is required to be more or less a certain value. Others take virtually any value, which results in a transfer function like

output = input reference

hence, multiplying.

DAC

(dack) abbr. See D/A converter.

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