Mystery paper tape reader

Hi, I was digging through my collection at the weekend and came across this paper tape reader(?). Can anyone help me identfy it? I've put some pictures up on my blog here: http://www.pdp8.co.uk/2008/11/26/mystery-paper-tape-reader/ It is labelled on the front as a ?Paper Tape Comparator?. It has an optical array for scanning the tape and an adjustable width feeder to support 3 different sizes. I can't find any indication of its make which makes me wonder if its scratch built with bits from another device. On the back is a female 25 pin D socket which I assume to be an RS232 outlet. There is also a 3 pin power socket in a format I don?t recognise. Any information would be greatly appreciated. Thanks, Toby -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.