Powering Yaesu FT-11R from an external supply

Question

I have downloaded the schematic for the FT-11R. It shows a "Contact Unit" as the interface between the rest of the radio and the supplied battery which is 4.8 VDC. The radio is supposed to be able to operate up to 9.6 VDC.The problem is that the supplied battery pack and the radio have 4 pins going from the radio to the battery pack. Clearly, one pin is + 4.8 VDC, one is ground. The problem is what is the function of the other two pins?One is labeled "Battery Select" and the other "Adjust" on the schematic, but what do these really do? Has anyone simply hooked up the + and minus leads to a bench power supply without causing any harm?de Rich, W6APZ