Multiface

The Multiface One — and its later Multiface 128 and Multiface 3 variants — was a hardware cartridge sold by Romantic Robot that plugged into the ZX Spectrum’s rear expansion edge connector and could freeze any running program at the press of a button. Once frozen, the user could search memory for specific values (looking for a lives counter or a score), edit individual bytes, disassemble code, and save the entire 48 KB (or 128 KB) memory state to tape, microdrive, or disk for later restoration.

Marketed as a “backup and development tool” — the legally defensible framing — the Multiface was in practice the technical engine of late-1980s POKE culture. The magazine pages full of Infinite Lives POKEs in 1985-89 were largely the product of readers with Multifaces. The Spectrum scene’s distinctive memory-inspection habit, and the community of cheat-finders that grew up around it, depended on this single £40 cartridge.

Fast facts

• Manufacturer: Romantic Robot
• Released: 1986
• Platform: ZX Spectrum
• Function: Freeze, peek, poke, save
• Price: £39.95 for the One in 1988, falling to £34.95 by 1989; the 128 and Three were £5 dearer
• Also included: a Kempston-compatible joystick interface, on the One
• Controversy: its maker expected the 1988 Copyright Act to end UK sales

Capabilities

Feature	Use
Freeze	Stop any running program
Search	Find specific values in memory
Poke	Modify memory directly
Save	Snapshot entire memory state
Toolkit	Disassemble, examine code

How it worked

1. Press red button - Hardware asserts NMI on the Z80, vectoring through $0066
2. Multiface ROM pages in - The cartridge maps its own ROM into low memory and jumps into its menu
3. Search/modify - Find lives counter, edit memory, disassemble code
4. Save snapshot - The full 48 KB (or 128 KB) memory state goes to tape or disk
5. Resume - Multiface restores the saved CPU state and unmaps its ROM, returning to the host program

The NMI freezer trick is what makes Multiface a hardware tool rather than software: NMI is non-maskable, so even programs that disabled IRQ couldn’t prevent the freeze.

Product variants

Model	Year	Target machine	Notes
Multiface One	1986	48K Spectrum	Original; tape and Microdrive snapshots, with a Kempston-compatible joystick interface built in
Multiface 128	1987	“any other Spectrum”	Romantic Robot’s general-purpose part for everything below the +3, not a 128K-only device
Multiface 3	1988	+3	Required because Amstrad changed the I/O port map (the +2A/+3 broke the original Multiface). Sold with or without a through port

The machine targets in that table are Romantic Robot’s own, taken from its advertising rather than from later convention: “MULTIFACE 3 for Spectrum+ 3, MULTIFACE 128 for any other Spectrum, MULTIFACE 1 for 48K Spectrum”.

I/O ports

Port	Used by
$1F	Multiface I
$3F	Multiface III
$BF	Multiface III, Multiface 128 v2

Creating Cheats

The typical POKE hunting process:

Step	Action
1	Note current lives (e.g., 3)
2	Search memory for value 3
3	Lose a life (now 2)
4	Search again for 2
5	Narrow down to correct address
6	POKE to maximum value

Controversy

The legal question was not left to hindsight — Romantic Robot raised it itself, in its own advertising, and turned it into a sales pitch. By Your Sinclair 42 the copy opened:

Because of possible implications of the coming new Copyright Act the MULTIFACE may soon be NO LONGER SOLD in the UK. This is YOUR LAST CHANCE to buy the ESSENTIAL SPECTRUM ADD-ON.

The legislation was the Copyright, Designs and Patents Act 1988. Romantic Robot offered £10 off every Multiface “to give EVERYBODY an opportunity to acquire a MULTIFACE whilst still possible”.

That is the most useful thing to know about the device’s legal standing: not that commentators later found it ambiguous, but that the manufacturer expected to be legislated out of the British market and said so in print while still taking orders.

Magazine Integration

Multiface became part of the ecosystem:

• Magazines published POKE addresses found with it
• Readers submitted discoveries
• POKE pages became regular features
• Created community participation

Other Platforms

Similar devices appeared:

Device	Platform
Action Replay	C64, Amiga
Pro Action Replay	Consoles
Game Genie	Consoles

Legacy

The Multiface is a defining piece of Spectrum-era third-party hardware. It is, alongside the Kempston joystick interface and the Currah μSource, one of the platform’s most-cited add-ons. Its technical model — NMI-triggered freezer, paged ROM with embedded toolkit, full memory snapshot — became the template for similar devices on other platforms: the Datel Action Replay on the C64 and Amiga, the Pro Action Replay on consoles, and (with different mechanics) the Game Genie.

Its cultural legacy is the community of cheat-finders and the magazine pages they wrote, which together turned the Spectrum scene into one of the few amateur-computing cultures of the era that systematically inspected the running software it bought.

Why the Multiface matters for Code Like It’s 198x

The Project’s pedagogical stance — that the Spectrum learner is expected to understand the running program in memory, not just the source text — is the Multiface user’s stance. Shadowkeep’s room-data table is something a 1987 reader with a Multiface would have found, modified, and shared on a CRASH Tips page. The curriculum doesn’t ask the learner to operate a Multiface, but it teaches Spectrum programming with the same view of the machine the Multiface presented: memory is inspectable, modifiable, and legible. Every Shadowkeep unit assumes this; the Multiface is one of the historical reasons that assumption is reasonable.

See also

• POKE culture — The cultural phenomenon the Multiface enabled.
• CRASH, Your Sinclair — Magazines whose POKE columns ran on Multiface-found cheats.
• Z80 — NMI vector $0066 is a CPU feature.
• Action Replay — The C64/Amiga equivalent.
• Game Genie — The console-era equivalent.
• Sinclair ZX Spectrum