diff --git a/Machines/PCCompatible/KeyboardMapper.hpp b/Machines/PCCompatible/KeyboardMapper.hpp
new file mode 100644
index 000000000..65f060a60
--- /dev/null
+++ b/Machines/PCCompatible/KeyboardMapper.hpp
@@ -0,0 +1,104 @@
+//
+//  KeyboardMapper.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 24/11/2023.
+//  Copyright © 2023 Thomas Harte. All rights reserved.
+//
+
+#ifndef KeyboardMapper_hpp
+#define KeyboardMapper_hpp
+
+#include "../KeyboardMachine.hpp"
+
+namespace PCCompatible {
+
+class KeyboardMapper: public MachineTypes::MappedKeyboardMachine::KeyboardMapper {
+	public:
+		uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) const override {
+			using k = Inputs::Keyboard::Key;
+			switch(key) {
+				case k::Escape:		return 1;
+
+				case k::k1:			return 2;
+				case k::k2:			return 3;
+				case k::k3:			return 4;
+				case k::k4:			return 5;
+				case k::k5:			return 6;
+				case k::k6:			return 7;
+				case k::k7:			return 8;
+				case k::k8:			return 9;
+				case k::k9:			return 10;
+				case k::k0:			return 11;
+
+				case k::Hyphen:		return 12;
+				case k::Equals:		return 13;
+				case k::Backspace:	return 14;
+
+				case k::Tab:		return 15;
+				case k::Q:			return 16;
+				case k::W:			return 17;
+				case k::E:			return 18;
+				case k::R:			return 19;
+				case k::T:			return 20;
+				case k::Y:			return 21;
+				case k::U:			return 22;
+				case k::I:			return 23;
+				case k::O:			return 24;
+				case k::P:			return 25;
+
+				case k::OpenSquareBracket:	return 26;
+				case k::CloseSquareBracket:	return 27;
+				case k::Enter:				return 28;
+
+				case k::LeftControl:
+				case k::RightControl:		return 29;
+
+				case k::A:			return 30;
+				case k::S:			return 31;
+				case k::D:			return 32;
+				case k::F:			return 33;
+				case k::G:			return 34;
+				case k::H:			return 35;
+				case k::J:			return 36;
+				case k::K:			return 37;
+				case k::L:			return 38;
+
+				case k::Semicolon:	return 39;
+				case k::Quote:		return 40;
+				case k::BackTick:	return 41;
+
+				case k::LeftShift:	return 42;
+				case k::Backslash:	return 43;
+
+				case k::Z:			return 55;
+				case k::X:			return 45;
+				case k::C:			return 46;
+				case k::V:			return 47;
+				case k::B:			return 48;
+				case k::N:			return 49;
+				case k::M:			return 50;
+
+				case k::Comma:			return 51;
+				case k::FullStop:		return 52;
+				case k::ForwardSlash:	return 53;
+				case k::RightShift:		return 54;
+
+				case k::LeftOption:
+				case k::RightOption:	return 56;
+				case k::Space:			return 57;
+				case k::CapsLock:		return 58;
+
+				case k::NumLock:		return 69;
+				case k::ScrollLock:		return 70;
+
+				default:	return MachineTypes::MappedKeyboardMachine::KeyNotMapped;
+			}
+
+			// TODO: extended functions, including all F keys and cursors.
+		}
+};
+
+}
+
+#endif /* KeyboardMapper_hpp */
diff --git a/Machines/PCCompatible/PCCompatible.cpp b/Machines/PCCompatible/PCCompatible.cpp
index 67eaf41ba..370b70c52 100644
--- a/Machines/PCCompatible/PCCompatible.cpp
+++ b/Machines/PCCompatible/PCCompatible.cpp
@@ -9,6 +9,7 @@
 #include "PCCompatible.hpp"
 
 #include "DMA.hpp"
+#include "KeyboardMapper.hpp"
 #include "PIC.hpp"
 #include "PIT.hpp"
 
@@ -27,6 +28,7 @@
 #include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
 
 #include "../AudioProducer.hpp"
+#include "../KeyboardMachine.hpp"
 #include "../ScanProducer.hpp"
 #include "../TimedMachine.hpp"
 
@@ -82,12 +84,15 @@ class KeyboardController {
 			return key;
 		}
 
-	private:
 		void post(uint8_t value) {
+			if(mode_ == Mode::NoIRQsIgnoreInput) {
+				return;
+			}
 			input_ = value;
 			pic_.apply_edge<1>(true);
 		}
 
+	private:
 		enum class Mode {
 			NormalOperation = 0b01,
 			NoIRQsIgnoreInput = 0b11,
@@ -900,7 +905,8 @@ class ConcreteMachine:
 	public Machine,
 	public MachineTypes::TimedMachine,
 	public MachineTypes::AudioProducer,
-	public MachineTypes::ScanProducer
+	public MachineTypes::ScanProducer,
+	public MachineTypes::MappedKeyboardMachine
 {
 	public:
 		ConcreteMachine(
@@ -1049,6 +1055,15 @@ class ConcreteMachine:
 			}
 		}
 
+		// MARK: - MappedKeyboardMachine.
+		MappedKeyboardMachine::KeyboardMapper *get_keyboard_mapper() override {
+			return &keyboard_mapper_;
+		}
+
+		void set_key_state(uint16_t key, bool is_pressed) override {
+			keyboard_.post(uint8_t(key | (is_pressed ? 0x00 : 0x80)));
+		}
+
 	private:
 		PIC pic_;
 		DMA dma_;
@@ -1062,6 +1077,8 @@ class ConcreteMachine:
 		PIT pit_;
 		PPI ppi_;
 
+		PCCompatible::KeyboardMapper keyboard_mapper_;
+
 		struct Context {
 			Context(PIT &pit, DMA &dma, PPI &ppi, PIC &pic, MDA &mda) :
 				segments(registers),
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 464c16bdd..80effae5b 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -1145,6 +1145,7 @@
 		4267A9C72B0C26FA008A59BB /* PIT.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = PIT.hpp; sourceTree = "<group>"; };
 		4267A9C82B0D4EC2008A59BB /* PIC.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = PIC.hpp; sourceTree = "<group>"; };
 		4267A9C92B0D4F17008A59BB /* DMA.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = DMA.hpp; sourceTree = "<group>"; };
+		4267A9CA2B111ED2008A59BB /* KeyboardMapper.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = KeyboardMapper.hpp; sourceTree = "<group>"; };
 		4281572E2AA0334300E16AA1 /* Carry.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Carry.hpp; sourceTree = "<group>"; };
 		428168372A16C25C008ECD27 /* LineLayout.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = LineLayout.hpp; sourceTree = "<group>"; };
 		428168392A37AFB4008ECD27 /* DispatcherTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = DispatcherTests.mm; sourceTree = "<group>"; };
@@ -2368,6 +2369,7 @@
 				4267A9C72B0C26FA008A59BB /* PIT.hpp */,
 				4267A9C82B0D4EC2008A59BB /* PIC.hpp */,
 				4267A9C92B0D4F17008A59BB /* DMA.hpp */,
+				4267A9CA2B111ED2008A59BB /* KeyboardMapper.hpp */,
 			);
 			path = PCCompatible;
 			sourceTree = "<group>";