diff --git a/Machines/Enterprise/Enterprise.cpp b/Machines/Enterprise/Enterprise.cpp
index 418c06de2..a01608751 100644
--- a/Machines/Enterprise/Enterprise.cpp
+++ b/Machines/Enterprise/Enterprise.cpp
@@ -225,26 +225,38 @@ template <bool has_disk_controller> class ConcreteMachine:
 			using PartialMachineCycle = CPU::Z80::PartialMachineCycle;
 			const uint16_t address = cycle.address ? *cycle.address : 0x0000;
 
-			// TODO: possibly apply an access penalty.
+			// Calculate an access penalty, if applicable.
 			HalfCycles penalty;
-			if(is_video_[address >> 14]) {
-				// TODO.
-			} else {
-				switch(cycle.operation) {
-					default: break;
+			switch(cycle.operation) {
+				default: break;
 
-					case CPU::Z80::PartialMachineCycle::ReadStart:
-					case CPU::Z80::PartialMachineCycle::WriteStart:
-						if(wait_mode_ == WaitMode::OnAllAccesses) {
-							penalty = HalfCycles(2);
-						}
-					break;
+				// For non-video pauses, insert during the initial part of the bus cycle.
+				case CPU::Z80::PartialMachineCycle::ReadStart:
+				case CPU::Z80::PartialMachineCycle::WriteStart:
+					if(!is_video_[address >> 14] && wait_mode_ == WaitMode::OnAllAccesses) {
+						penalty = HalfCycles(2);
+					}
+				break;
+				case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
+					if(!is_video_[address >> 14] && wait_mode_ != WaitMode::None) {
+						penalty = HalfCycles(2);
+					}
+				break;
 
-					case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
-						if(wait_mode_ != WaitMode::None) {
-							penalty = HalfCycles(2);
-						}
-					break;
+				// Video pauses: insert right at the end of the bus cycle.
+				case CPU::Z80::PartialMachineCycle::ReadOpcode:
+				case CPU::Z80::PartialMachineCycle::Read:
+				case CPU::Z80::PartialMachineCycle::Write:
+					if(is_video_[address >> 14]) {
+						// TODO.
+					}
+				break;
+
+				case CPU::Z80::PartialMachineCycle::Input:
+				case CPU::Z80::PartialMachineCycle::Output: {
+					if((address & 0xf0) == 0x80) {
+						// TODO.
+					}
 				}
 			}
 
diff --git a/Machines/Enterprise/Nick.cpp b/Machines/Enterprise/Nick.cpp
index be9bfd0c1..139285e49 100644
--- a/Machines/Enterprise/Nick.cpp
+++ b/Machines/Enterprise/Nick.cpp
@@ -92,7 +92,17 @@ uint8_t Nick::read([[maybe_unused]] uint16_t address) {
 	return 0xff;
 }
 
-//int c;
+Cycles Nick::get_time_until_z80_slot() const {
+	// Place Z80 accesses as the first six cycles in each sixteen-cycle window.
+	// That models video accesses as being the final ten. Which has the net effect
+	// of responding to the line parameter table interrupt flag as soon as it's
+	// loaded.
+
+	// i.e. 0 -> 0, 1 -> 15 ... 15 -> 1.
+	return Cycles(
+		15 ^ ((horizontal_counter_ + 15) & 15)
+	);
+}
 
 void Nick::run_for(Cycles duration) {
 	constexpr int line_length = 912;
@@ -455,7 +465,7 @@ void Nick::set_output_type(OutputType type, bool force_flush) {
 
 // MARK: - Sequence points.
 
-Cycles Nick::get_next_sequence_point() {
+Cycles Nick::get_next_sequence_point() const {
 	// TODO: the below is incorrect; unit test and correct.
 	// Changing to e.g. Cycles(1) reveals the relevant discrepancy.
 //	return Cycles(1);
diff --git a/Machines/Enterprise/Nick.hpp b/Machines/Enterprise/Nick.hpp
index 31911e90d..75b220c12 100644
--- a/Machines/Enterprise/Nick.hpp
+++ b/Machines/Enterprise/Nick.hpp
@@ -23,11 +23,12 @@ class Nick {
 		uint8_t read(uint16_t address);
 
 		void run_for(Cycles);
+		Cycles get_time_until_z80_slot() const;
 
 		void set_scan_target(Outputs::Display::ScanTarget *scan_target);
 		Outputs::Display::ScanStatus get_scaled_scan_status() const;
 
-		Cycles get_next_sequence_point();
+		Cycles get_next_sequence_point() const;
 
 		/*!
 			@returns The current state of the interrupt line — @c true for active;