Expand a single UART (RX/TX) serial port into 8 additional 
   serial ports
• On-board LEDs indicate which channel has been opened
• Supports baud rates greater then 1M Baud
• Easily connect two Serial Port Expanders together to get 16    additional serial ports
• Operating voltage: 3.3V to 5V
• Power consumption: 0.15mA at 3.3 volts

DATASHEET

https://www.atlas-scientific.com/_files/_datasheets/_circuit/serial_port_expander_datasheet.pdf

 8:1 Serial Port Expander Datasheet
 Arduino UNO + 1 Serial Port Expander code

 Serial Port Expander CAD Footprint File (*.dxf)

 Raspberry Pi Sample Code

https://www.atlas-scientific.com/_files/_app_notes/RoHS%20Certificate.pdf

https://www.atlas-scientific.com/_files/_app_notes/CE%20Certificate.pdf