diff --git a/src/devices/bus/rs232/null_modem.cpp b/src/devices/bus/rs232/null_modem.cpp
index 525da0af415..8c182989ff6 100644
--- a/src/devices/bus/rs232/null_modem.cpp
+++ b/src/devices/bus/rs232/null_modem.cpp
@@ -13,6 +13,7 @@ null_modem_device::null_modem_device(const machine_config &mconfig, const char *
 	m_rs232_databits(*this, "RS232_DATABITS"),
 	m_rs232_parity(*this, "RS232_PARITY"),
 	m_rs232_stopbits(*this, "RS232_STOPBITS"),
+	m_flow(*this, "FLOW_CONTROL"),
 	m_input_count(0),
 	m_input_index(0),
 	m_timer_poll(nullptr),
@@ -36,6 +37,10 @@ static INPUT_PORTS_START(null_modem)
 	MCFG_RS232_DATABITS("RS232_DATABITS", RS232_DATABITS_8, "Data Bits", null_modem_device, update_serial)
 	MCFG_RS232_PARITY("RS232_PARITY", RS232_PARITY_NONE, "Parity", null_modem_device, update_serial)
 	MCFG_RS232_STOPBITS("RS232_STOPBITS", RS232_STOPBITS_1, "Stop Bits", null_modem_device, update_serial)
+	PORT_START("FLOW_CONTROL")
+	PORT_CONFNAME(0x01, 0x00, "Flow Control")
+	PORT_CONFSETTING(0x00, "Off")
+	PORT_CONFSETTING(0x01, "On")
 INPUT_PORTS_END
 
 ioport_constructor null_modem_device::device_input_ports() const
@@ -102,7 +107,7 @@ void null_modem_device::queue()
 			m_input_count = m_stream->input(m_input_buffer, sizeof(m_input_buffer));
 		}
 
-		if (m_input_count != 0 && m_rts == 0)
+		if (m_input_count != 0 && (m_rts == 0 || !m_flow->read()))
 		{
 			transmit_register_setup(m_input_buffer[m_input_index++]);
 
diff --git a/src/devices/bus/rs232/null_modem.h b/src/devices/bus/rs232/null_modem.h
index 15792f448e7..028614788d6 100644
--- a/src/devices/bus/rs232/null_modem.h
+++ b/src/devices/bus/rs232/null_modem.h
@@ -42,6 +42,7 @@ private:
 	required_ioport m_rs232_databits;
 	required_ioport m_rs232_parity;
 	required_ioport m_rs232_stopbits;
+	required_ioport m_flow;
 
 	UINT8 m_input_buffer[1000];
 	UINT32 m_input_count;
diff --git a/src/mame/drivers/tv990.cpp b/src/mame/drivers/tv990.cpp
index 8d71191bb59..12961d674eb 100644
--- a/src/mame/drivers/tv990.cpp
+++ b/src/mame/drivers/tv990.cpp
@@ -369,7 +369,7 @@ static MACHINE_CONFIG_START( tv990, tv990_state )
 	MCFG_INS8250_OUT_DTR_CB(DEVWRITELINE(RS232B_TAG, rs232_port_device, write_dtr))
 	MCFG_INS8250_OUT_RTS_CB(DEVWRITELINE(RS232B_TAG, rs232_port_device, write_rts))
 	MCFG_INS8250_OUT_TX_CB(DEVWRITELINE(RS232B_TAG, rs232_port_device, write_txd))
-	MCFG_INS8250_OUT_INT_CB(WRITELINE(tv990_state, uart0_irq))
+	MCFG_INS8250_OUT_INT_CB(WRITELINE(tv990_state, uart1_irq))
 
 	MCFG_RS232_PORT_ADD(RS232A_TAG, default_rs232_devices, nullptr)
 	MCFG_RS232_RXD_HANDLER(DEVWRITELINE(UART0_TAG, ns16450_device, rx_w))