This connector converter can convert a 6.4 x 4.5mm male connector with center pin to a 5.5 x 2.1mm male connector.
The back end of this converter is a 6.4 x 4.5mm female jack:
It can plug to a 6.4 x 4.5mm male connector, convert it to a 5.5 x 2.1mm male connector like this:
Note: 6.4 x 4.5mm connector with center pin is widely used on Fujitsu, Panasonic and Sony laptop power adapters.