GRiD Model 1900 question

Hi, I picked up a GRiD Model 1900 pen-based DOS machine today. HSC Electronics is selling them for $20 each here in Californie. I haven't found much in the way of websites, pictures, etc. of this machine. Does anyone know of any out there? What I know so far is that they seem to be V20 powered 2 mb RAM based machines with little expandability but a nice LCD display. It has a semi-standard [compatible but weird pinout] port for a keyboard. There is a port on the side that I hope is a serial port and not a CGA or some such thing. How do you get data in and out of these machines? I was wondering what the little door on the bottom of the machine is. Someone in past e-mails on the net mentioned that it was for an IDE hard drive connection. Might this be true? I haven't powered it up yet as I have yet to order a power supply for it [Monday] but am intrigued enough to pour a few bucks into it to see if it works properly. With piqued curiousity, Thomas 0(a)0000000.com