Ancient HP resources

My classic computer interests primarily center around early-to-mid 1970s DEC Unibus systems and peripherals. In my computer center I have a couple 1970-72 vintage Hewlett Packard X-Y plotters, an HP7202A and an HP7210A. In college back in the 70s we had an HP7200A, which is pretty much identical to the HP7202A except that the 7202A will support 100, 150, and 300 baud, while the 7200A only supports 100 baud. I am going to hook up the 7202A plotter to my PDP-11/40. It appears to support both 20mA and EIA (RS232) connections. I'd like to connect it to my M7814 20mA DZ11. Currently the only device connected to my 20mA DZ11 is an ASR-33 teletype. All other terminals (DecScopes, DecWriters, VT05, VT100, etc) are connected to the M7819 EIA DZ11. Does anyone here know of anyone who has worked with these kinds of plotters, connecting them to either a PDP-11 or an HP minicomputer? They were made to work in-line with an ASR-33, or they could be used somewhat like a printer, where you could send simple ASCII commands like PLTL for "Plot Line" or PLTP for "Plot Points", and then you would send it X,Y coordinates like "0001,0500". Back in the old days, we used programs like HPPLOT.BAS to do the plotting, and we had a program called CHGEN.BAS to generate characters so we could label our plots. I have these programs loaded on my PDP-11/40. Are there forums for classic HP hardware such as this, where I could get in touch with others who may have experience connecting these devices to my ancient minicomputer? I have Googled and there is not much info out on the web that I can find. Some info is on http://www.hpmuseum.net, but not much elsewhere. I have the User Manual and the Service Manual, as well as several pieces of marketing material on these plotters. Pictures of the plotter can be found at: http://www.woffordwitch.com/HP7202.asp Thanks in advance for any info or advice that anyone might be able to offer. Ashley Carder http://www.woffordwitch.com