<p>A synchronous 4-bit up/down decade counter symbol (74LS192) in accordance with ANSI/IEEE Std. 91-1984 and IEC Publication 60617-12.
</p><p>This logic symbol is based on the TI SN74LS192 datasheet. 
</p><p><br></p><p>This was the first edition of the <i>TTL Data Book</i> that used the IEEE Std. 91 symbols. Volume 1 contained a tutorial on how to read and create these symbols.<a rel="nofollow" class="external autonumber" href="http://focus.ti.com/lit/ml/sdyz001a/sdyz001a.pdf">[1]</a> The tutorial was written by Fred Mann, the TI representative on IEEE subcommittee that created this style of symbols. He was also on the IEC technical committee.
</p><p>This symbol is also similar to figure 5.13-16 in IEEE Std 91A-1991.
</p>
This image was drawn using Adobe Photoshop Elements 3.0 by Michael Holley, June 2007.
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6 June 2007 (original upload date)
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