Building a USB Serial to 5 Pin Domino DIN Cable

 The BBC Micro computer uses an almost extinct 5 Pin "Domino" DIN connector for its RS423 (RS232 compatible) serial port. I wanted a neat cable to connect my BBC computers to things like SerialFS and TCPSer but there wasn't really anything on the market that was neat and compact.

I needed a USB to RS232 level cable, but without a DB9 on the end, as the USB Serial chip is often inside it. Many cables available online are TTL level which makes them unsuitable. After a bit of hunting I discovered the programming cable for the Kenwood TM-D710 Radio uses RS232 levels and Tx, Rx, Gnd, RTS and CTS which is exactly what we need, so I set about modifying it.