Cool 4004 based calculator

Hi, Sellam (and all), Unicom was a company that was started up as a spinoff of IC maker American Microsystems (AMI). There's little out there about the history of the company in its early days, but it's possible that Unicom initially started out simply OEMing machines from Busicom, until they had developed their own chips. Busicom for a time had an exclusive on the 4004 as the result of their joint effort with Intel to develop a reconfigurable general purpose calculator chipset, which ended up morphing into a microprocessor. I do know that Busicom did OEM their machines to a number of different marketers of early electronic calculators, and perhaps Unicom was one of them. Busicom's machine with the 4004 was the 141PF (they weren't shy about recycling model numbers, as the 141 was a lower-cost version of Busicom's first machine, the 162, which was indeed a discrete transistor machine). The 141PF was a printing only machine. Looking at patent information, the architecture of the design was such that it could be adapted (part of the whole idea that spurred the development of the 4004 in the first place) to use a display rather than a printer. So, my guess (and it's just that at this point) is that the machine you have is an adaptation of the original 141PF design, done either by Busicom either on their own, or under contract to Unicom, which was sold under the Unicom brand name in North America. Later, AMI sold off the Unicom division to Rockwell, and for a while, Rockwell sold handheld calculators under this brand, then abandoned the Unicom brand and sold their machines (using their own chips) under the Rockwell brand, as well as through other OEMs. In any case, this is an AWESOME find! I want pix! I don't blame you for being stoked about this one. Hope that you can get it running! Regards, Rick Bensene The Old Calculator Web Museum http://oldcalculatormuseum.com