What exactally does the G2 do other than convert from a 24 to 28 pin chip ?

What I mean is , does it internally short pins 1,2,28,27 and 26 on the board , or is their something else on the board .

Reason I ask is I want to use my Autoprom on a 7747 today , and I would have to order a G2 to do so the proper way . Just wondering if I could make something up quick.

Thanks

TOM