I2C through PC parallel port, serial port and/or USB port - please help

[kony]

Any such bus would be" internal", not available for outside use.
AFAIK, smarcard reader inclused with mobos would be USB or RS232
serial.

Most(?) motherboards in recent years do have an I2C bus external
connection header, often called "SMBus"... consult user's manual
for it's location.

 

[Adam]

Looks like you're right since my motherboard's User's Manual says
the following about the SMBus Connector (5-1 pin SMB):
"This connector allows you to connect SMBus (System Management Bus) devices.
SMBus devices communicate by means of the SMBus with an SMBus host and/or
other SMBus devices. SMBus is a specific implementation of an I2C bus,
which is a multi-device bus; that is, multiple chips can be connected to
the same bus and each one can act as a master by initiating data transfer."

However, this connector is accessible directly from the motherboard and
requires the computer case to be open.

 

[kony]

However, this connector is accessible directly from the motherboard and
requires the computer case to be open.

A with any other motherboard pin-header plus dongle arrangement,
you can use a cable to mount the desired connector anywhere you
want it, such that it's accessible from outside the case.