diff --git a/Components/6850/6850.cpp b/Components/6850/6850.cpp
index 1001c01ac..4776cb1a8 100644
--- a/Components/6850/6850.cpp
+++ b/Components/6850/6850.cpp
@@ -57,6 +57,7 @@ void ACIA::write(int address, uint8_t value) {
 	} else {
 		if((value&3) == 3) {
 			transmit.reset_writing();
+			transmit.write(true);
 			request_to_send.reset_writing();
 		} else {
 			switch(value & 3) {
diff --git a/Components/SerialPort/SerialPort.cpp b/Components/SerialPort/SerialPort.cpp
index c9d9dc506..3d903154d 100644
--- a/Components/SerialPort/SerialPort.cpp
+++ b/Components/SerialPort/SerialPort.cpp
@@ -19,14 +19,25 @@ void Line::advance_writer(int cycles) {
 	while(!events_.empty()) {
 		if(events_.front().delay < cycles) {
 			cycles -= events_.front().delay;
+			write_cycles_since_delegate_call_ += events_.front().delay;
+			const auto old_level = level_;
+
 			auto iterator = events_.begin() + 1;
 			while(iterator != events_.end() && iterator->type != Event::Delay) {
 				level_ = iterator->type == Event::SetHigh;
 				++iterator;
 			}
 			events_.erase(events_.begin(), iterator);
+
+			if(old_level != level_) {
+				if(read_delegate_) {
+					read_delegate_->serial_line_did_change_output(this, Storage::Time(write_cycles_since_delegate_call_, clock_rate_), level_);
+					write_cycles_since_delegate_call_ = 0;
+				}
+			}
 		} else {
 			events_.front().delay -= cycles;
+			write_cycles_since_delegate_call_ += cycles;
 			break;
 		}
 	}
@@ -50,6 +61,7 @@ void Line::write(int cycles, int count, int levels) {
 		events_[event].type = Event::Delay;
 		events_[event].delay = cycles;
 		events_[event+1].type = (levels&1) ? Event::SetHigh : Event::SetLow;
+		levels >>= 1;
 		event += 2;
 	}
 }
@@ -66,10 +78,22 @@ void Line::reset_writing() {
 void Line::flush_writing() {
 	remaining_delays_ = 0;
 	for(const auto &event : events_) {
+		bool new_level = level_;
 		switch(event.type) {
 			default: break;
-			case Event::SetHigh:	level_ = true;	break;
-			case Event::SetLow:		level_ = false;	break;
+			case Event::SetHigh:	new_level = true;	break;
+			case Event::SetLow:		new_level = false;	break;
+			case Event::Delay:
+				write_cycles_since_delegate_call_ += event.delay;
+			continue;
+		}
+
+		if(new_level != level_) {
+			level_ = new_level;
+			if(read_delegate_) {
+				read_delegate_->serial_line_did_change_output(this, Storage::Time(write_cycles_since_delegate_call_, clock_rate_), level_);
+				write_cycles_since_delegate_call_ = 0;
+			}
 		}
 	}
 	events_.clear();
@@ -78,3 +102,8 @@ void Line::flush_writing() {
 bool Line::read() {
 	return level_;
 }
+
+void Line::set_read_delegate(ReadDelegate *delegate) {
+	read_delegate_ = delegate;
+	write_cycles_since_delegate_call_ = 0;
+}
diff --git a/Components/SerialPort/SerialPort.hpp b/Components/SerialPort/SerialPort.hpp
index 82eadc2a3..5f8628588 100644
--- a/Components/SerialPort/SerialPort.hpp
+++ b/Components/SerialPort/SerialPort.hpp
@@ -10,6 +10,7 @@
 #define SerialPort_hpp
 
 #include <vector>
+#include "../../Storage/Storage.hpp"
 
 namespace Serial {
 
@@ -53,6 +54,11 @@ class Line {
 		/// @returns The instantaneous level of this line.
 		bool read();
 
+		struct ReadDelegate {
+			virtual void serial_line_did_change_output(Line *line, Storage::Time time_since_last_change, bool new_level) = 0;
+		};
+		void set_read_delegate(ReadDelegate *delegate);
+
 	private:
 		struct Event {
 			enum Type {
@@ -64,6 +70,9 @@ class Line {
 		int remaining_delays_ = 0;
 		bool level_ = false;
 		int clock_rate_ = 0;
+
+		ReadDelegate *read_delegate_ = nullptr;
+		int write_cycles_since_delegate_call_ = 0;
 };
 
 /*!
diff --git a/Machines/AtariST/AtariST.cpp b/Machines/AtariST/AtariST.cpp
index 6277489ff..c13c352bc 100644
--- a/Machines/AtariST/AtariST.cpp
+++ b/Machines/AtariST/AtariST.cpp
@@ -21,6 +21,7 @@
 #include "../../ClockReceiver/ForceInline.hpp"
 
 #include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
+#include "../../Outputs/Log.hpp"
 
 #include "../Utility/MemoryPacker.hpp"
 #include "../Utility/MemoryFuzzer.hpp"
@@ -30,8 +31,50 @@ namespace ST {
 
 const int CLOCK_RATE = 8000000;
 
-using Target = Analyser::Static::Target;
+/*!
+	A receiver for the Atari ST's "intelligent keyboard" commands, which actually cover
+	keyboard input and output and mouse handling.
+*/
+class IntelligentKeyboard:
+	public Serial::Line::ReadDelegate {
+	public:
+		IntelligentKeyboard(Serial::Line &input, Serial::Line &output) : output_line_(output) {
+			input.set_read_delegate(this);
+		}
 
+		void serial_line_did_change_output(Serial::Line *, Storage::Time time_since_last_change, bool new_level) final {
+			// Figure out how many bits have passed. TODO: in fixed point?
+			const float number_of_bits = time_since_last_change.get<float>() * 7812.5f + bit_offset_;
+			bit_offset_ = fmodf(number_of_bits, 1.0f);
+
+			int bits_remaining = int(number_of_bits);
+			while(bits_remaining--) {
+				if(!bit_count_) {
+					// Check for a potential start bit.
+					if(!new_level) {
+						bit_count_ = 10;
+						command_ = 0;
+					}
+				} else {
+					command_ >>= 1;
+					command_ |= new_level ? 0 : 0x200;
+					--bit_count_;
+
+					if(!bit_count_) {
+						LOG("[IKBD] Should perform " << PADHEX(2) << ((command_ >> 1) & 0xff));
+					}
+				}
+			}
+		}
+
+	private:
+		int bit_count_ = 0;
+		int command_ = 0;
+		Serial::Line &output_line_;
+		float bit_offset_ = 0.0f;
+};
+
+using Target = Analyser::Static::Target;
 class ConcreteMachine:
 	public Atari::ST::Machine,
 	public CPU::MC68000::BusHandler,
@@ -42,7 +85,8 @@ class ConcreteMachine:
 			keyboard_acia_(Cycles(500000)),
 			midi_acia_(Cycles(500000)),
 			ay_(audio_queue_),
-			speaker_(ay_) {
+			speaker_(ay_),
+			ikbd_(keyboard_acia_->transmit, keyboard_acia_->receive) {
 			set_clock_rate(CLOCK_RATE);
 			speaker_.set_input_rate(CLOCK_RATE / 4);
 
@@ -380,6 +424,8 @@ class ConcreteMachine:
 		Outputs::Speaker::LowpassSpeaker<GI::AY38910::AY38910> speaker_;
 		HalfCycles cycles_since_audio_update_;
 
+		IntelligentKeyboard ikbd_;
+
 		std::vector<uint16_t> ram_;
 		std::vector<uint16_t> rom_;