I was digging through my collection at the weekend and came across a small portable paper tape reader(?). Can anyone help me identfy it?

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.

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.