diff --git a/src/emu/bus/rs232/terminal.h b/src/emu/bus/rs232/terminal.h
index d56f312834e..771437fe6e4 100644
--- a/src/emu/bus/rs232/terminal.h
+++ b/src/emu/bus/rs232/terminal.h
@@ -27,6 +27,8 @@ protected:
 	virtual void rcv_complete();
 	virtual void send_key(UINT8 code);
 
+	virtual DECLARE_WRITE_LINE_MEMBER( input_dtr ) { output_dsr(state); }
+
 private:
 	required_ioport m_io_term_txbaud;
 	required_ioport m_io_term_rxbaud;
diff --git a/src/emu/machine/i8251.c b/src/emu/machine/i8251.c
index ff11f7d3848..3d82f7876a4 100644
--- a/src/emu/machine/i8251.c
+++ b/src/emu/machine/i8251.c
@@ -696,7 +696,7 @@ WRITE_LINE_MEMBER(i8251_device::write_cts)
 
 WRITE_LINE_MEMBER(i8251_device::write_dsr)
 {
-	m_dsr = state;
+	m_dsr = !state;
 }
 
 WRITE_LINE_MEMBER(i8251_device::write_rxc)