Quantity   Component name
1 × Psion Organiser II I'm using the 32K XP model (sometimes also called the LA) introduced in 1987. There was a cheaper model with 8K RAM called the CM, and a 'deluxe' model called the LZ which was introduced in 1989 and had a 4-line display. Ooh, fancy!
1 × Psion Comms Link A remarkably hard-to-find Organiser peripheral. Vintage units from the 80s have an RS232 port, modern units have a USB.
1 × Raspberry Pi 3/4/Zero, connected to Internet
1 × USB to 9V DC 'barrel jack' cable This will allow you to power your Organiser & Comms Link via a USB power bank - cheaper than relying on 9V batteries!
1 × Serial Pi HAT Details to follow once I've got one!
1 × USB power bank, ideally with 2 outputs To power your Pi and your Organiser/Comms Link