diff --git a/src/emu/machine/tms9902.c b/src/emu/machine/tms9902.c
index 3f818fcde06..3eaed05011f 100644
--- a/src/emu/machine/tms9902.c
+++ b/src/emu/machine/tms9902.c
@@ -553,6 +553,7 @@ void tms9902_device::reset_uart()
 	m_DSCH = false;
 	m_TIMELP = false;
 	m_INT = false;
+	m_CTSin = false;
 
 	m_TMR = 0;
 	m_STOPB = 0;