diff --git a/dc11.cpp b/dc11.cpp
index 54582ad..5ed1bd8 100644
--- a/dc11.cpp
+++ b/dc11.cpp
@@ -131,7 +131,7 @@ void dc11::operator()()
 
 				registers[line_nr * 4 + 0] |= 128;  // DONE: bit 7
 
-				if (registers[line_nr * 4 + 0] & 64)  // interrupts enabled?
+				if (is_rx_interrupt_enabled(line_nr))
 					trigger_interrupt(line_nr);
 
 				have_data[line_nr].notify_all();
@@ -151,6 +151,16 @@ void dc11::reset()
 {
 }
 
+bool dc11::is_rx_interrupt_enabled(const int line_nr)
+{
+	return !!(registers[line_nr * 4 + 0] & 64);
+}
+
+bool dc11::is_tx_interrupt_enabled(const int line_nr)
+{
+	return !!(registers[line_nr * 4 + 2] & 64);
+}
+
 uint8_t dc11::read_byte(const uint16_t addr)
 {
 	uint16_t v = read_word(addr & ~1);
@@ -192,10 +202,11 @@ uint16_t dc11::read_word(const uint16_t addr)
 			recv_buffers[line_nr].erase(recv_buffers[line_nr].begin());
 
 			// still data in buffer? generate interrupt
-			if (recv_buffers[line_nr].empty() == false && (registers[line_nr * 4] & 64)) {
+			if (recv_buffers[line_nr].empty() == false) {
 				registers[line_nr * 4 + 0] |= 128;  // DONE: bit 7
 
-				trigger_interrupt(line_nr);
+				if (is_rx_interrupt_enabled(line_nr))
+					trigger_interrupt(line_nr);
 			}
 		}
 	}
@@ -236,7 +247,7 @@ void dc11::write_word(const uint16_t addr, uint16_t v)
 		// TODO handle failed transmit
 		printf("%ld\r\n", write(pfds[dc11_n_lines + line_nr].fd, &c, 1));
 
-		if (registers[line_nr * 4 + 2] & 64)
+		if (is_tx_interrupt_enabled(line_nr))
 			trigger_interrupt(line_nr);
 	}
 
diff --git a/dc11.h b/dc11.h
index 83416f7..afc34cd 100644
--- a/dc11.h
+++ b/dc11.h
@@ -42,6 +42,8 @@ private:
         std::mutex        input_lock[dc11_n_lines];
 
 	void trigger_interrupt(const int line_nr);
+	bool is_rx_interrupt_enabled(const int line_nr);
+	bool is_tx_interrupt_enabled(const int line_nr);
 
 public:
 	dc11(const int base_port, bus *const b);