So I am working on speeding up a nixie tube speedometer, in this question: , but this brought up another question. Would having matching baud rates for multiple external devices speed up processes.

In the case of the other question the OBD-II device is running at 38400 where the Nixie Tubes are running at 9600. Since I'm taking the info from the OBD-II connector and doing a little math and sending it to the Nixie Tubes, would it be beneficial to have the same baud rate for both devices?

Now... before you down-vote this question for making some sort of "duplicate" this also answers a question about having a "master" serial hub and having communication between different "slave" serial devices.

2 Answers 2


It all depends on how often speed is being reported via the OBD-II connection. If the report rate is faster than the update rate of the tubes then yes, increasing the speed of the tube circuit (not necessarily the connection itself) can have an effect (as long as the tubes themselves can keep up, of course). If the speed is being reported slower than the tubes then don't bother unless you have other reasons for increasing it, since both bit rates are already so much faster than the human mind can see, much less process.


If you are using different serial ports for each device (eg: using software serial for at least one of them on a Uno, or using separate hardware serial on a Mega2560), then it really doesn't matter whether they use the same baud rate or not.

If you are somehow multiplexing the same serial port (eg: input only from one device, output only to the other; or some external multiplexing hardware) then there might be a slight gain in not needing to change the baud rate when switching between devices, but probably not noticable.

If either or both devices have some option to communicate faster, that might speed up your system - independent of whether they use the SAME rate.

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