None of the models I know of have a serial port.
I know you said you can't use a USB > serial adapter, just curious why?

the experience i had with them is that a lot of devices will not be detected via a usb to serial adapter, have no clue why but they just dont work with a lot of things.
suppose i could try and hunt down an old cheap lappy that might work, the usb to serial cables seem very flakey best of times and the drivers hinder more than help am sure of it