Expandable Serial Port Multiplexer
The Expandable Serial Port Multiplexer allows a single RS-232 serial port to service multiple instruments that require RS-232 ports. An ATmega8 microcontroller serves as the master processor, which is connected to a PC through a serial port. Multiple slaves (ATmega162 microcontrollers) connect to the master via a parallel bus to provide two serial ports each.
Link: http://www.circuitcellar.com/avr2004/DA3724.html
The Expandable Serial Port Multiplexer allows a single RS-232 serial port to service multiple instruments that require RS-232 ports. An ATmega8 microcontroller serves as the master processor, which is connected to a PC through a serial port. Multiple slaves (ATmega162 microcontrollers) connect to the master via a parallel bus to provide two serial ports each.
Link: http://www.circuitcellar.com/avr2004/DA3724.html