mux demux shield

hello everyone. i need a serial port multiplexer. i there any ready made one, or is there any mux demux shield that is broken out so that i can connect it to any pin in arduino?

Something like this? It might be what you are looking for.

Onions.

I’m trying to use not that one.
because i need to use I2C and i want that common pin somewhere else. otherwise i will only have 1 analog pin left.
but well, i guess it’s easier to rewire the pin rather than making my own mux shield.

That link didn't take me to a serial multiplexer shield?

Note that if you have something that uses I2C it doesn't stop you using other I2C devices at the same time, it is a bus after all.

The problem with a serial port is that is is almost impossible to multiplex because it needs to be active all the time and multiplexing in this context is short for "time division multiplexing" so there will be times when one port or the other is not active. Also they need to be able to work simultaneously, which can't happen with time division multiplexing.

Adding an extra serial port might be an option and you can get an I2C UART chip that could do this for you. Maybe that is what the missing link is about. You can always use a Mega, they have four ports.