diff --git a/Machines/Commodore/Plus4/Plus4.cpp b/Machines/Commodore/Plus4/Plus4.cpp
index da5cbf94c..f23d1a968 100644
--- a/Machines/Commodore/Plus4/Plus4.cpp
+++ b/Machines/Commodore/Plus4/Plus4.cpp
@@ -115,7 +115,7 @@ public:
 		// NTSC: 7159090?
 		// i.e. colour subcarriers multiplied by two?
 
-		set_clock_rate(7159090);	// TODO.
+		set_clock_rate(8867240);	// TODO.
 
 		const auto kernel = ROM::Name::Plus4KernelPALv5;
 		const auto basic = ROM::Name::Plus4BASIC;
@@ -141,8 +141,9 @@ public:
 		const uint16_t address,
 		uint8_t *const value
 	) {
-		// TODO: calculate length of this bus operation.
-		const auto length = Cycles(5);
+		// Determine from the TED video subsystem the length of this clock cycle as perceived by the 6502,
+		// relative to the master clock.
+		const auto length = video_.cycle_length(operation == CPU::MOS6502::BusOperation::Ready);
 
 		// Update other subsystems.
 		// TODO: timers decrement at a 894 KHz rate for NTSC television systems, 884 KHZ for PAL systems.
@@ -179,6 +180,7 @@ public:
 
 					case 0xff08:
 						// TODO: keyboard.
+						// For now: all keys unpressed.
 						*value = 0xff;
 					break;
 
@@ -255,6 +257,7 @@ private:
 	}
 
 	void page_rom() {
+		// TODO: allow other ROM selection. And no ROM?
 		map_.page<PagerSide::Read, 0x8000, 16384>(basic_.data());
 		map_.page<PagerSide::Read, 0xc000, 16384>(kernel_.data());
 	}
diff --git a/Machines/Commodore/Plus4/Video.hpp b/Machines/Commodore/Plus4/Video.hpp
index 8efe2dbb0..c09c2262a 100644
--- a/Machines/Commodore/Plus4/Video.hpp
+++ b/Machines/Commodore/Plus4/Video.hpp
@@ -126,6 +126,18 @@ public:
 //		printf("bitmap:%d c256:%d ntsc:%d 40col:%d; base:%04x\n", bitmap_mode_, characters_256_, is_ntsc_, columns_40_, screen_memory_address_);
 	}
 
+	Cycles cycle_length([[maybe_unused]] bool is_ready) const {
+		// TODO: the complete test is more than this.
+		// TODO: if this is a RDY cycle, can reply with time until end-of-RDY.
+		const bool is_long_cycle = refresh_;
+
+		if(is_ntsc_) {
+			return is_long_cycle ? Cycles(8) : Cycles(4);
+		} else {
+			return is_long_cycle ? Cycles(10) : Cycles(5);
+		}
+	}
+
 	// Outer clock is [NTSC or PAL] colour subcarrier * 2.
 	//
 	// 65 cycles = 64µs?
@@ -212,13 +224,25 @@ public:
 					case OutputState::Sync:		crt_.output_sync(time_in_state_);								break;
 					case OutputState::Burst:	crt_.output_default_colour_burst(time_in_state_);				break;
 					case OutputState::Border:	crt_.output_level<uint16_t>(time_in_state_, background_[4]);	break;
-					case OutputState::Pixels:	crt_.output_level<uint16_t>(time_in_state_, background_[0]);	break;
+					case OutputState::Pixels:	crt_.output_data(time_in_state_, time_in_state_);				break;
 				}
 				time_in_state_ = 0;
+
+				output_state_ = state;
+				if(output_state_ == OutputState::Pixels) {
+					pixels_ = reinterpret_cast<uint16_t *>(crt_.begin_data(384, 2));
+				}
 			}
-			output_state_ = state;
 			time_in_state_ += period;
 
+			// Output pixels. TODO: properly.
+			if(pixels_) {
+				for(int c = 0; c < period; c++) {
+					pixels_[c] = ((c + horizontal_counter_)  & 1) ? 0x0000 : 0xffff;
+				}
+				pixels_ += period;
+			}
+
 			//
 			// Advance for current period.
 			//
@@ -346,6 +370,7 @@ private:
 		Pixels,
 	} output_state_ = OutputState::Blank;
 	int time_in_state_ = 0;
+	uint16_t *pixels_ = nullptr;
 
 	std::array<uint16_t, 5> background_{};
 	std::array<uint8_t, 5> raw_background_{};