RS232 buffer and RS232 multiplexer

Wenjun Huang

Other Parts Discussed in Thread: TS12A12511

Is there such a thing as RS232 buffer and RS232 multiplexer?

RS232 is different from normal interface as it gives a -3 to -25V for logic low and +3 to +25V for logic high vs normal interface which gives a 0 for logic low and +5V for logic high.

Hence selecting a buffer for RS232 requires the buffer to be able to take in -25V to +25V and output accordingly.

I would like the buffer to be a fanout, meaning 1 RS232 input to the buffer will generate 2 RS232 output with same voltage level as input.

Similarly, a multiplexer for RS232 would need to take such voltage.

Could recommend such chip if possible.

over 13 years ago

0 Wenjun Huang over 13 years ago

Expert 1770 points

I find a chip called TS12A12511. It is advertised as RS232 analog switch (guess due to the high voltage range it can take.

I am intending to do redundancy (by using 2 processor card and 2 rs232 device). But the TS12A12511 will be a single point failure. Hence, I would need to look at the reliability figures. http://focus.ti.com/quality/docs/singlesearchresults.tsp?&templateId=5909&navigationId=11213&appType=folders&searchType=orderableOption&partialSearch=false&mtbfType=true&orderablePartNumber=TS12A12511DCNR

I do not know how to interpret the table shown. Any guidance how to interpret the reliability table? If I use this chip to run continuously for 21 days, what is the likelihood of this chip spoiling?

0 Ron Michallick over 13 years ago

TI__Guru**** 165326 points

Wenjun,

Is data flow unidirectional (one way)?
Do the 2 RS232 outputs need to be combined at the destination?
It seems that you just want to buffer a RS232 signal and send it to two remote RS232 receivers.

What is the purpose for the redundancy?

Regards,
Ron Michallick

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RS232 buffer and RS232 multiplexer