Glossary of Terms:
 
To Host port
This type of serial port can be found on many MIDI instruments (in addition to the MIDI jacks) and allows direct connection from the MIDI device to a personal computer without the need for a seperate MIDI interface. The interface cable used is different for a Macintosh computer than a PC. Certain settings must be made on the computer to use the port for MIDI. On a PC, a special serial port driver must also be installed.
Source: Yamaha

Also refered as:
  EIA-232   RS-232   To Host connector   serial port
Related terms:
  Firewire   MIDI   To Host cable   To Host switch   USB   serial port cable   serial port driver