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:
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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:
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Note: 6.4 x 4.5mm connector with center pin is widely used on Fujitsu, Panasonic and Sony laptop power adapters.