The best replacement for serial port is parallel port.

The best alternatives to serial port are rated as following:
★★★★★  parallel port
★★★★  usb
★★  com port
★  rs232
★  uart
★  usb port
★  printer port
★  ethernet port
  game port
  mscomm
  lpt
  vga port
  parallel

Your alternative for serial port is not listed? Suggest!
Speaking about serial port, one probably shouldn't forget about putty.

Other search terms related to serial port and their ratings are:
★★★★★ putty
★★★★★ hyperterminal
★★★★ labview
★ matlab gui
★ loopback
max232
You have in mind a companion for serial port and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of serial port in all years. Click on graph for more.
serial port
parallel port
usb