diff --git a/bus.cpp b/bus.cpp
index 5ffb4a0..bf962c0 100644
--- a/bus.cpp
+++ b/bus.cpp
@@ -1120,13 +1120,16 @@ void bus::writeWord(const uint16_t a, const uint16_t value, const d_i_space_t s)
 	write(a, wm_word, value, rm_cur, s);
 }
 
-uint16_t bus::readUnibusByte(const uint32_t a)
+uint8_t bus::readUnibusByte(const uint32_t a)
 {
-	return m->readByte(a);
+	uint8_t v = m->readByte(a);
+	DOLOG(debug, false, "readUnibusByte[%08o]=%03o", a, v);
+	return v;
 }
 
 void bus::writeUnibusByte(const uint32_t a, const uint8_t v)
 {
+	DOLOG(debug, false, "writeUnibusByte[%08o]=%03o", a, v);
 	m->writeByte(a, v);
 }
 
diff --git a/bus.h b/bus.h
index 1f1c24e..8c577e1 100644
--- a/bus.h
+++ b/bus.h
@@ -156,7 +156,7 @@ public:
 	uint16_t readWord(const uint16_t a, const d_i_space_t s = i_space);
 	uint16_t peekWord(const uint16_t a);
 
-	uint16_t readUnibusByte(const uint32_t a);
+	uint8_t  readUnibusByte(const uint32_t a);
 
 	write_rc_t write    (const uint16_t a, const word_mode_t word_mode, uint16_t value, const rm_selection_t mode_selection, const d_i_space_t s = i_space);
 	void       writeByte(const uint16_t a, const uint8_t value) { write(a, wm_byte, value, rm_cur); }