My name is Bob, I have a Summasketch+. The 4pin square connector is for the power pack. I do not know what the RJ11 connector is for. I have been trying to locate drivers for this pad to try it with my WinXP. No luck there, only found Win9x and NT. I was hoping that I could use a magnetic pen with it. However, from what I am reading, it doesn't sound like that will work. If anyone know what I need to make this work, please let me know. I hate to trash it. I have 4 boys and my Net time is very limited, so you are welcome to email me at intdoc(a)charter.net. Thanks all!