82928A System monitor: Provides the necessary hardware to aid in developing and debugging assembly language programs for HP Series 80 Personal Computers. The HP 00085-15007 (or 00087-15007), 82928A and 82929A form a complete set of tools. The 82928A System monitor is described in the HP85 Assembler ROM manual. This manual is currently available on the MoHPC CDROM (http://www.hpmuseum.org) collection (if you are interested in the 85 then purchasing the MpHPC collection should be a priority as it also contains the 85 service manual). Somebody has promised me a scan of the 85 assembler manual, so it should appear shortly in the www.series80.org site as well. Last but certainly not least is John Shadbolt's site (http://www.vintagecomputers.freeserve.co.uk/hp80) **vp