An electronic instrument including: an upstream port UPPT provided on a
side surface SF1 of the electronic instrument; a downstream port DWPT
provided on a side surface SF2 which is a surface of the electronic
instrument and opposite to the side surface SF1; and a data transfer
control device which is connected to the upstream port UPPT and the
downstream port DWPT and controls data transfer through the upstream port
UPPT and data transfer through the downstream port DWPT.