# serial multiplexer

**URL:** <https://community.sparkfun.com/t/serial-multiplexer/10804>\
**Category:** SparkFun Site Questions/Comments\
**Created:** [April 13, 2009, 6:19pm UTC](https://community.sparkfun.com/t/serial-multiplexer/10804 "2009-04-13T18:19:27Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ozoney](https://avatars.discourse-cdn.com/v4/letter/o/bb73d2/32.png) [@ozoney](https://community.sparkfun.com/u/ozoney)\
**Post date:** [April 13, 2009, 6:19pm UTC](https://community.sparkfun.com/t/serial-multiplexer/10804/1 "2009-04-13T18:19:27Z")

</div>

How do I tie in two different serial devices to this serial multiplexer? If I have two devices with vcc,gnd,rx,tx, where to they hook in? And then what goes to GPIO? and what is the truth table for selecting the device?

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