Ok, I have one uart interface (TXD GPIO 14, RXD GPIO 15). I want at least one more uart interface.
Bit banging: Use two unrelated spare GPIOs. I understand that timing is a problem on a standard linux. Would it be reliable with very low baudrate?
Switching: RPI decides when to talk to which device. Using e.g. CD4066BC.
spi to 2 x uart bridge: Didn't find a suitable part (availability, price, dil package)
usb to uart: Expensive
Are there other options? I'm inclined to switching, if it can be done. What would you advise?