diff --git a/src/mess/drivers/thomson.c b/src/mess/drivers/thomson.c
index 740ed95202d..a0adf32de67 100644
--- a/src/mess/drivers/thomson.c
+++ b/src/mess/drivers/thomson.c
@@ -673,8 +673,7 @@ static MACHINE_CONFIG_START( to7, thomson_state )
 	MCFG_PIA_IRQB_HANDLER(WRITELINE(thomson_state, thom_irq_1))
 
 /* TODO: CONVERT THIS TO A SLOT DEVICE (RF 57-932) */
-	MCFG_DEVICE_ADD("acia", MOS6551, 0)
-	//MCFG_MOS6551_XTAL(XTAL_1_8432MHz)
+	MCFG_DEVICE_ADD("acia", MOS6551, XTAL_1_8432MHz)
 	MCFG_MOS6551_TXD_HANDLER(DEVWRITELINE("rs232", rs232_port_device, write_txd))
 
 	/// 2400 7N2