diff --git a/.gitattributes b/.gitattributes
index 2faba7e64c9..f38e379d509 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -668,6 +668,8 @@ src/emu/cpu/psx/rcnt.c svneol=native#text/plain
 src/emu/cpu/psx/rcnt.h svneol=native#text/plain
 src/emu/cpu/psx/sio.c svneol=native#text/plain
 src/emu/cpu/psx/sio.h svneol=native#text/plain
+src/emu/cpu/psx/siodev.c svneol=native#text/plain
+src/emu/cpu/psx/siodev.h svneol=native#text/plain
 src/emu/cpu/rsp/rsp.c svneol=native#text/plain
 src/emu/cpu/rsp/rsp.h svneol=native#text/plain
 src/emu/cpu/rsp/rsp_dasm.c svneol=native#text/plain
@@ -4649,6 +4651,8 @@ src/mame/machine/jalcrpt.h svneol=native#text/plain
 src/mame/machine/jumpshot.c svneol=native#text/plain
 src/mame/machine/jvs13551.c svneol=native#text/plain
 src/mame/machine/jvs13551.h svneol=native#text/plain
+src/mame/machine/k573cass.c svneol=native#text/plain
+src/mame/machine/k573cass.h svneol=native#text/plain
 src/mame/machine/kabuki.c svneol=native#text/plain
 src/mame/machine/kaneko_calc3.c svneol=native#text/plain
 src/mame/machine/kaneko_calc3.h svneol=native#text/plain
@@ -4833,6 +4837,8 @@ src/mame/machine/vsnes.c svneol=native#text/plain
 src/mame/machine/williams.c svneol=native#text/plain
 src/mame/machine/wrally.c svneol=native#text/plain
 src/mame/machine/xevious.c svneol=native#text/plain
+src/mame/machine/zndip.c svneol=native#text/plain
+src/mame/machine/zndip.h svneol=native#text/plain
 src/mame/machine/znsec.c svneol=native#text/plain
 src/mame/machine/znsec.h svneol=native#text/plain
 src/mame/machine/zs01.c svneol=native#text/plain
@@ -7138,6 +7144,8 @@ src/mess/machine/psxcd.c svneol=native#text/plain
 src/mess/machine/psxcd.h svneol=native#text/plain
 src/mess/machine/psxcddrv.c svneol=native#text/plain
 src/mess/machine/psxcddrv.h svneol=native#text/plain
+src/mess/machine/psxcport.c svneol=native#text/plain
+src/mess/machine/psxcport.h svneol=native#text/plain
 src/mess/machine/radio86.c svneol=native#text/plain
 src/mess/machine/rm380z.c svneol=native#text/plain
 src/mess/machine/rmnimbus.c svneol=native#text/plain
diff --git a/src/emu/cpu/cpu.mak b/src/emu/cpu/cpu.mak
index eeba32d2b82..9f8564c6773 100644
--- a/src/emu/cpu/cpu.mak
+++ b/src/emu/cpu/cpu.mak
@@ -931,7 +931,7 @@ $(CPUOBJ)/mips/mips3drc.o:	$(CPUSRC)/mips/mips3drc.c \
 
 ifneq ($(filter PSX,$(CPUS)),)
 OBJDIRS += $(CPUOBJ)/psx
-CPUOBJS += $(CPUOBJ)/psx/psx.o $(CPUOBJ)/psx/gte.o $(CPUOBJ)/psx/dma.o $(CPUOBJ)/psx/irq.o $(CPUOBJ)/psx/mdec.o $(CPUOBJ)/psx/rcnt.o $(CPUOBJ)/psx/sio.o
+CPUOBJS += $(CPUOBJ)/psx/psx.o $(CPUOBJ)/psx/gte.o $(CPUOBJ)/psx/dma.o $(CPUOBJ)/psx/irq.o $(CPUOBJ)/psx/mdec.o $(CPUOBJ)/psx/rcnt.o $(CPUOBJ)/psx/sio.o $(CPUOBJ)/psx/siodev.o
 DASMOBJS += $(CPUOBJ)/psx/psxdasm.o
 endif
 
diff --git a/src/emu/cpu/psx/psx.c b/src/emu/cpu/psx/psx.c
index 6d99c5c6468..bf021fec8ed 100644
--- a/src/emu/cpu/psx/psx.c
+++ b/src/emu/cpu/psx/psx.c
@@ -3167,44 +3167,6 @@ psxcpu_device *psxcpu_device::getcpu( device_t &device, const char *cputag )
 	return downcast<psxcpu_device *>( device.subdevice( cputag ) );
 }
 
-void psxcpu_device::install_sio_handler( device_t &device, const char *cputag, int n_port, psx_sio_handler p_f_sio_handler )
-{
-	psxsio_device *sio;
-
-	switch( n_port )
-	{
-	case 0:
-		sio = getcpu( device, cputag )->subdevice<psxsio_device>("sio0");
-		break;
-	case 1:
-		sio = getcpu( device, cputag )->subdevice<psxsio_device>("sio1");
-		break;
-	default:
-		return;
-	}
-
-	sio->install_handler( p_f_sio_handler );
-}
-
-void psxcpu_device::sio_input( device_t &device, const char *cputag, int n_port, int n_mask, int n_data )
-{
-	psxsio_device *sio;
-
-	switch( n_port )
-	{
-	case 0:
-		sio = getcpu( device, cputag )->subdevice<psxsio_device>("sio0");
-		break;
-	case 1:
-		sio = getcpu( device, cputag )->subdevice<psxsio_device>("sio1");
-		break;
-	default:
-		return;
-	}
-
-	sio->input( n_mask, n_data );
-}
-
 READ32_HANDLER( psxcpu_device::gpu_r )
 {
 	return m_gpu_read_handler( space, offset, mem_mask );
diff --git a/src/emu/cpu/psx/psx.h b/src/emu/cpu/psx/psx.h
index b42ec76c4b1..de722f094fb 100644
--- a/src/emu/cpu/psx/psx.h
+++ b/src/emu/cpu/psx/psx.h
@@ -143,8 +143,6 @@ public:
 	DECLARE_READ32_MEMBER( gpu_r );
 
 	static psxcpu_device *getcpu( device_t &device, const char *cputag );
-	static void install_sio_handler( device_t &device, const char *cputag, int n_port, psx_sio_handler p_f_sio_handler );
-	static void sio_input( device_t &device, const char *cputag, int n_port, int n_mask, int n_data );
 
 protected:
 	psxcpu_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, address_map_constructor internal_map);
diff --git a/src/emu/cpu/psx/sio.c b/src/emu/cpu/psx/sio.c
index b7da951febc..8f4906a5623 100644
--- a/src/emu/cpu/psx/sio.c
+++ b/src/emu/cpu/psx/sio.c
@@ -6,7 +6,6 @@
  */
 
 #include "sio.h"
-#include "includes/psx.h"
 
 #define VERBOSE_LEVEL ( 0 )
 
@@ -38,7 +37,6 @@ psxsio1_device::psxsio1_device(const machine_config &mconfig, const char *tag, d
 
 psxsio_device::psxsio_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, UINT32 clock) :
 	device_t(mconfig, type, "PSX SIO", tag, owner, clock),
-	m_fn_handler(NULL),
 	m_irq_handler(*this)
 {
 }
@@ -82,11 +80,20 @@ void psxsio_device::device_start()
 	save_item( NAME( m_tx_shift ) );
 	save_item( NAME( m_rx_bits ) );
 	save_item( NAME( m_tx_bits ) );
-}
 
-void psxsio_device::install_handler( psx_sio_handler p_f_sio_handler )
-{
-	m_fn_handler = p_f_sio_handler;
+	deviceCount = 0;
+
+	for( device_t *device = first_subdevice(); device != NULL; device = device->next() )
+	{
+		psxsiodev_device *psxsiodev = dynamic_cast<psxsiodev_device *>(device);
+		if( psxsiodev != NULL )
+		{
+			devices[ deviceCount++ ] = psxsiodev;
+			psxsiodev->m_psxsio = this;
+		}
+	}
+
+	input_update();
 }
 
 void psxsio_device::sio_interrupt()
@@ -140,6 +147,22 @@ void psxsio_device::sio_timer_adjust()
 	m_timer->adjust( n_time );
 }
 
+void psxsio_device::output( int data, int mask )
+{
+	int new_outputdata = ( m_outputdata & ~mask ) | ( data & mask );
+	int new_mask = m_outputdata ^ new_outputdata;
+
+	if( new_mask != 0 )
+	{
+		m_outputdata = new_outputdata;
+
+		for( int i = 0; i < deviceCount; i++ )
+		{
+			devices[ i ]->data_in( m_outputdata, new_mask );
+		}
+	}
+}
+
 void psxsio_device::device_timer(emu_timer &timer, device_timer_id tid, int param, void *ptr)
 {
 	verboselog( machine(), 2, "sio tick\n" );
@@ -167,18 +190,15 @@ void psxsio_device::device_timer(emu_timer &timer, device_timer_id tid, int para
 		m_tx_shift >>= 1;
 		m_tx_bits--;
 
-		if( m_fn_handler != NULL )
+		if( type() == PSX_SIO0 )
 		{
-			if( type() == PSX_SIO0 )
-			{
-				m_tx &= ~PSX_SIO_OUT_CLOCK;
-				(*m_fn_handler)( machine(), m_tx );
-				m_tx |= PSX_SIO_OUT_CLOCK;
-			}
-
-			(*m_fn_handler)( machine(), m_tx );
+			m_tx &= ~PSX_SIO_OUT_CLOCK;
+			output( m_tx, PSX_SIO_OUT_CLOCK | PSX_SIO_OUT_DATA );
+			m_tx |= PSX_SIO_OUT_CLOCK;
 		}
 
+		output( m_tx, PSX_SIO_OUT_CLOCK | PSX_SIO_OUT_DATA );
+
 		if( m_tx_bits == 0 &&
 			( m_control & SIO_CONTROL_TX_IENA ) != 0 )
 		{
@@ -259,13 +279,7 @@ WRITE32_MEMBER( psxsio_device::write )
 				m_tx &= ~PSX_SIO_OUT_DTR;
 			}
 
-			if( ( ( m_tx ^ m_tx_prev ) & PSX_SIO_OUT_DTR ) != 0 )
-			{
-				if( m_fn_handler != NULL )
-				{
-					(*m_fn_handler)( machine(), m_tx );
-				}
-			}
+			output( m_tx, PSX_SIO_OUT_DTR );
 
 			m_tx_prev = m_tx;
 
@@ -341,10 +355,20 @@ READ32_MEMBER( psxsio_device::read )
 	return data;
 }
 
-void psxsio_device::input( int n_mask, int n_data )
+void psxsio_device::input_update()
 {
-	verboselog( machine(), 1, "psx_sio_input( %s, %02x, %02x )\n", tag(), n_mask, n_data );
-	m_rx = ( m_rx & ~n_mask ) | ( n_data & n_mask );
+	int data = 0;
+
+	for( int i = 0; i < deviceCount; i++ )
+	{
+		data |= devices[ i ]->m_dataout;
+	}
+
+	int mask = data ^ m_rx;
+
+	verboselog( machine(), 1, "input_update( %s, %02x, %02x )\n", tag(), mask, data );
+
+	m_rx = data;
 
 	if( ( m_rx & PSX_SIO_IN_DSR ) != 0 )
 	{
diff --git a/src/emu/cpu/psx/sio.h b/src/emu/cpu/psx/sio.h
index 4d4267718d4..fc1d45632a3 100644
--- a/src/emu/cpu/psx/sio.h
+++ b/src/emu/cpu/psx/sio.h
@@ -11,23 +11,14 @@
 #define __PSXSIO_H__
 
 #include "emu.h"
+#include "siodev.h"
 
 extern const device_type PSX_SIO0;
 extern const device_type PSX_SIO1;
 
-typedef void ( *psx_sio_handler )( running_machine &, int );
-
 #define MCFG_PSX_SIO_IRQ_HANDLER(_devcb) \
 	devcb = &psxsio_device::set_irq_handler(*device, DEVCB2_##_devcb); \
 
-#define PSX_SIO_OUT_DATA ( 1 )	/* COMMAND */
-#define PSX_SIO_OUT_DTR ( 2 )	/* ATT */
-#define PSX_SIO_OUT_RTS ( 4 )
-#define PSX_SIO_OUT_CLOCK ( 8 )	/* CLOCK */
-#define PSX_SIO_IN_DATA ( 1 )	/* DATA */
-#define PSX_SIO_IN_DSR ( 2 )	/* ACK */
-#define PSX_SIO_IN_CTS ( 4 )
-
 #define SIO_BUF_SIZE ( 8 )
 
 #define SIO_STATUS_TX_RDY ( 1 << 0 )
@@ -53,12 +44,10 @@ public:
 	// static configuration helpers
 	template<class _Object> static devcb2_base &set_irq_handler(device_t &device, _Object object) { return downcast<psxsio_device &>(device).m_irq_handler.set_callback(object); }
 
-	void install_handler( psx_sio_handler p_f_sio_handler );
-
 	DECLARE_WRITE32_MEMBER( write );
 	DECLARE_READ32_MEMBER( read );
 
-	void input( int n_mask, int n_data );
+	void input_update();
 
 protected:
 	// device-level overrides
@@ -67,6 +56,7 @@ protected:
 	virtual void device_post_load();
 
 private:
+	void output( int data, int mask );
 	void sio_interrupt();
 	void sio_timer_adjust();
 
@@ -86,9 +76,14 @@ private:
 	UINT32 m_rx_bits;
 
 	emu_timer *m_timer;
-	psx_sio_handler m_fn_handler;
 
 	devcb2_write_line m_irq_handler;
+
+	psxsiodev_device *devices[ 10 ];
+	int deviceCount;
+
+	int m_outputdata;
+	int m_inputdata;
 };
 
 class psxsio0_device : public psxsio_device
diff --git a/src/emu/cpu/psx/siodev.c b/src/emu/cpu/psx/siodev.c
new file mode 100644
index 00000000000..6faad6b2ba9
--- /dev/null
+++ b/src/emu/cpu/psx/siodev.c
@@ -0,0 +1,19 @@
+#include "sio.h"
+#include "siodev.h"
+
+psxsiodev_device::psxsiodev_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock) :
+	device_t(mconfig, type, name, tag, owner, clock)
+{
+}
+
+void psxsiodev_device::device_start()
+{
+	m_dataout = 0;
+}
+
+void psxsiodev_device::data_out( int data, int mask )
+{
+	m_dataout = ( m_dataout & ~mask ) | ( data & mask );
+
+	m_psxsio->input_update();
+}
diff --git a/src/emu/cpu/psx/siodev.h b/src/emu/cpu/psx/siodev.h
new file mode 100644
index 00000000000..51ea53e076c
--- /dev/null
+++ b/src/emu/cpu/psx/siodev.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "emu.h"
+
+#ifndef _PSXSIODEV_H_
+#define _PSXSIODEV_H_
+
+#define PSX_SIO_OUT_DATA ( 1 )	/* COMMAND */
+#define PSX_SIO_OUT_DTR ( 2 )	/* ATT */
+#define PSX_SIO_OUT_RTS ( 4 )
+#define PSX_SIO_OUT_CLOCK ( 8 )	/* CLOCK */
+#define PSX_SIO_IN_DATA ( 1 )	/* DATA */
+#define PSX_SIO_IN_DSR ( 2 )	/* ACK */
+#define PSX_SIO_IN_CTS ( 4 )
+
+class psxsio_device;
+
+class psxsiodev_device : public device_t
+{
+	friend class psxsio_device;
+
+public:
+	// construction/destruction
+	psxsiodev_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock);
+
+protected:
+	// device-level overrides
+	virtual void device_start();
+
+	void data_out( int data, int mask );
+
+private:
+	psxsio_device *m_psxsio;
+
+	virtual void data_in( int data, int mask ) = 0;
+	int m_dataout;
+};
+
+#endif
diff --git a/src/mame/drivers/ksys573.c b/src/mame/drivers/ksys573.c
index eb25523aaed..33a9adfe643 100644
--- a/src/mame/drivers/ksys573.c
+++ b/src/mame/drivers/ksys573.c
@@ -444,6 +444,7 @@ G: gun mania only, drives air soft gun (this game uses real BB bullet)
 #include "sound/cdda.h"
 #include "sound/mas3507d.h"
 #include "cdrom.h"
+#include "machine/k573cass.h"
 
 #define VERBOSE_LEVEL ( 0 )
 
@@ -1390,7 +1391,6 @@ static void update_mode( running_machine &machine )
 
 DRIVER_INIT_MEMBER(ksys573_state,konami573)
 {
-
 	psx_driver_init(machine());
 	atapi_init(machine());
 
@@ -1401,13 +1401,6 @@ DRIVER_INIT_MEMBER(ksys573_state,konami573)
 
 MACHINE_RESET_MEMBER(ksys573_state,konami573)
 {
-
-	if( machine().device<device_secure_serial_flash>("install_eeprom") )
-	{
-		/* security cart */
-		psx_sio_input( machine(), 1, PSX_SIO_IN_DSR, PSX_SIO_IN_DSR );
-	}
-
 	m_flash_bank = -1;
 
 	update_mode(machine());
@@ -3146,37 +3139,45 @@ MACHINE_CONFIG_END
 // Up to two carts can be used
 
 static MACHINE_CONFIG_DERIVED( konami573x, konami573 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( konami573y, konami573 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( konami573yi, konami573 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( konami573zi, konami573 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_ZS01_ADD(    "install_eeprom", "install_id" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573baitx, k573bait )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573dx, k573d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573dxi, k573d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573dxzi, k573d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 	MCFG_ZS01_ADD(    "game_eeprom", "game_id" )
@@ -3184,11 +3185,13 @@ static MACHINE_CONFIG_DERIVED( k573dxzi, k573d )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573dyi, k573d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573dyyi, k573d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 	MCFG_X76F100_ADD( "game_eeprom" )
@@ -3196,25 +3199,30 @@ static MACHINE_CONFIG_DERIVED( k573dyyi, k573d )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( k573dzi, k573d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_ZS01_ADD(    "install_eeprom", "install_id" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard1x, pccard1 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard1xi, pccard1 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard1yi, pccard1 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard1dxzi, pccard1d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 	MCFG_ZS01_ADD(    "game_eeprom", "game_id" )
@@ -3222,11 +3230,13 @@ static MACHINE_CONFIG_DERIVED( pccard1dxzi, pccard1d )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard1dzi, pccard1d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_ZS01_ADD(    "install_eeprom", "install_id" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard2yyi, pccard2 )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 	MCFG_X76F100_ADD( "game_eeprom" )
@@ -3234,6 +3244,7 @@ static MACHINE_CONFIG_DERIVED( pccard2yyi, pccard2 )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard2dxzi, pccard2d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F041_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 	MCFG_ZS01_ADD(    "game_eeprom", "game_id" )
@@ -3241,6 +3252,7 @@ static MACHINE_CONFIG_DERIVED( pccard2dxzi, pccard2d )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard2dyyi, pccard2d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_X76F100_ADD( "install_eeprom" )
 	MCFG_DS2401_ADD(  "install_id" )
 	MCFG_X76F100_ADD( "game_eeprom" )
@@ -3248,6 +3260,7 @@ static MACHINE_CONFIG_DERIVED( pccard2dyyi, pccard2d )
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_DERIVED( pccard2dzi, pccard2d )
+	MCFG_DEVICE_ADD("maincpu:sio1:k573cass", KONAMI573CASSETTE, 0)
 	MCFG_ZS01_ADD(    "install_eeprom", "install_id" )
 	MCFG_DS2401_ADD(  "install_id" )
 MACHINE_CONFIG_END
diff --git a/src/mame/drivers/taitogn.c b/src/mame/drivers/taitogn.c
index 9ae88418f2c..34ce1cc83f9 100644
--- a/src/mame/drivers/taitogn.c
+++ b/src/mame/drivers/taitogn.c
@@ -324,6 +324,7 @@ Type 3 (PCMCIA Compact Flash Adaptor + Compact Flash card, sealed together with
 #include "machine/at28c16.h"
 #include "machine/intelfsh.h"
 #include "machine/znsec.h"
+#include "machine/zndip.h"
 #include "machine/idectrl.h"
 #include "machine/mb3773.h"
 #include "sound/spu.h"
@@ -334,13 +335,15 @@ class taitogn_state : public psx_state
 public:
 	taitogn_state(const machine_config &mconfig, device_type type, const char *tag) :
 		psx_state(mconfig, type, tag),
-		m_znsec0(*this,"znsec0"),
-		m_znsec1(*this,"znsec1")
+		m_znsec0(*this,"maincpu:sio0:znsec0"),
+		m_znsec1(*this,"maincpu:sio0:znsec1"),
+		m_zndip(*this,"maincpu:sio0:zndip")
 	{
 	}
 
 	required_device<znsec_device> m_znsec0;
 	required_device<znsec_device> m_znsec1;
+	required_device<zndip_device> m_zndip;
 
 	intel_te28f160_device *m_biosflash;
 	intel_e28f400_device *m_pgmflash;
@@ -357,10 +360,6 @@ public:
 	int m_v;
 
 	UINT32 m_n_znsecsel;
-	UINT32 m_b_znsecport;
-	int m_n_dip_bit;
-	int m_b_lastclock;
-	emu_timer *m_dip_timer;
 
 	UINT32 m_coin_info;
 	UINT32 m_mux_data;
@@ -395,7 +394,6 @@ public:
 	DECLARE_DRIVER_INIT(coh3002t_mp);
 	DECLARE_DRIVER_INIT(coh3002t);
 	DECLARE_MACHINE_RESET(coh3002t);
-	TIMER_CALLBACK_MEMBER(dip_timer_fired);
 };
 
 
@@ -692,123 +690,15 @@ READ32_MEMBER(taitogn_state::znsecsel_r)
 	return m_n_znsecsel;
 }
 
-static void sio_znsec0_handler( running_machine &machine, int n_data )
-{
-	taitogn_state *state = machine.driver_data<taitogn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_CLOCK ) == 0 )
-	{
-		if( state->m_b_lastclock )
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, ( state->m_znsec0->step( ( n_data & PSX_SIO_OUT_DATA ) != 0 ) != 0 ) * PSX_SIO_IN_DATA );
-
-		state->m_b_lastclock = 0;
-	}
-	else
-	{
-		state->m_b_lastclock = 1;
-	}
-}
-
-static void sio_znsec1_handler( running_machine &machine, int n_data )
-{
-	taitogn_state *state = machine.driver_data<taitogn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_CLOCK ) == 0 )
-	{
-		if( state->m_b_lastclock )
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, ( state->m_znsec1->step( ( n_data & PSX_SIO_OUT_DATA ) != 0 ) != 0 ) * PSX_SIO_IN_DATA );
-
-		state->m_b_lastclock = 0;
-	}
-	else
-	{
-		state->m_b_lastclock = 1;
-	}
-}
-
-static void sio_pad_handler( running_machine &machine, int n_data )
-{
-	taitogn_state *state = machine.driver_data<taitogn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_DTR ) != 0 )
-	{
-		state->m_b_znsecport = 1;
-	}
-	else
-	{
-		state->m_b_znsecport = 0;
-	}
-
-	psx_sio_input( machine, 0, PSX_SIO_IN_DATA | PSX_SIO_IN_DSR, PSX_SIO_IN_DATA | PSX_SIO_IN_DSR );
-}
-
-static void sio_dip_handler( running_machine &machine, int n_data )
-{
-	taitogn_state *state = machine.driver_data<taitogn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_CLOCK ) == 0 )
-	{
-		if( state->m_b_lastclock )
-		{
-			int bit = ( ( state->ioport("DSW")->read() >> state->m_n_dip_bit ) & 1 );
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, bit * PSX_SIO_IN_DATA );
-			state->m_n_dip_bit++;
-			state->m_n_dip_bit &= 7;
-		}
-		state->m_b_lastclock = 0;
-	}
-	else
-	{
-		state->m_b_lastclock = 1;
-	}
-}
-
 WRITE32_MEMBER(taitogn_state::znsecsel_w)
 {
 	COMBINE_DATA( &m_n_znsecsel );
 
 	m_znsec0->select( ( m_n_znsecsel >> 2 ) & 1 );
 	m_znsec1->select( ( m_n_znsecsel >> 3 ) & 1 );
-
-	if( ( m_n_znsecsel & 0x80 ) == 0 )
-	{
-		psx_sio_install_handler( machine(), 0, sio_pad_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-	}
-	else if( ( m_n_znsecsel & 0x08 ) == 0 )
-	{
-		psx_sio_install_handler( machine(), 0, sio_znsec1_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-	}
-	else if( ( m_n_znsecsel & 0x04 ) == 0 )
-	{
-		psx_sio_install_handler( machine(), 0, sio_znsec0_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-	}
-	else
-	{
-		m_n_dip_bit = 0;
-		m_b_lastclock = 1;
-
-		psx_sio_install_handler( machine(), 0, sio_dip_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-
-		m_dip_timer->adjust( downcast<cpu_device *>(&space.device())->cycles_to_attotime( 100 ), 1 );
-	}
+	m_zndip->select( ( m_n_znsecsel & 0x8c ) != 0x8c );
 }
 
-TIMER_CALLBACK_MEMBER(taitogn_state::dip_timer_fired)
-{
-
-	psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, param * PSX_SIO_IN_DSR );
-
-	if( param )
-	{
-		m_dip_timer->adjust(machine().device<cpu_device>("maincpu")->cycles_to_attotime(50));
-	}
-}
-
-
 READ32_MEMBER(taitogn_state::boardconfig_r)
 {
 	/*
@@ -881,8 +771,6 @@ DRIVER_INIT_MEMBER(taitogn_state,coh3002t)
 	psx_driver_init(machine());
 	m_znsec0->init(tt10);
 	m_znsec1->init(tt16);
-	psx_sio_install_handler(machine(), 0, sio_pad_handler);
-	m_dip_timer = machine().scheduler().timer_alloc( timer_expired_delegate(FUNC(taitogn_state::dip_timer_fired),this), NULL );
 
 	UINT32 metalength;
 	memset(m_cis, 0xff, 512);
@@ -898,8 +786,6 @@ DRIVER_INIT_MEMBER(taitogn_state,coh3002t_mp)
 
 MACHINE_RESET_MEMBER(taitogn_state,coh3002t)
 {
-
-	m_b_lastclock = 1;
 	m_locked = 0x1ff;
 	install_handlers(machine(), 0);
 	m_control = 0;
@@ -951,8 +837,10 @@ static MACHINE_CONFIG_START( coh3002t, taitogn_state )
 	MCFG_CPU_ADD( "maincpu", CXD8661R, XTAL_100MHz )
 	MCFG_CPU_PROGRAM_MAP(taitogn_map)
 
-	MCFG_DEVICE_ADD("znsec0", ZNSEC, 0)
-	MCFG_DEVICE_ADD("znsec1", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:znsec0", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:znsec1", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:zndip", ZNDIP, 0)
+	MCFG_ZNDIP_DATA_HANDLER(IOPORT(":DSW"))
 
 	/* video hardware */
 	MCFG_PSXGPU_ADD( "maincpu", "gpu", CXD8654Q, 0x200000, XTAL_53_693175MHz )
diff --git a/src/mame/drivers/zn.c b/src/mame/drivers/zn.c
index 19e53ac01f5..277d57803f4 100644
--- a/src/mame/drivers/zn.c
+++ b/src/mame/drivers/zn.c
@@ -18,6 +18,7 @@
 #include "machine/nvram.h"
 #include "machine/mb3773.h"
 #include "machine/znsec.h"
+#include "machine/zndip.h"
 #include "machine/idectrl.h"
 #include "audio/taitosnd.h"
 #include "sound/2610intf.h"
@@ -35,19 +36,17 @@ public:
 	zn_state(const machine_config &mconfig, device_type type, const char *tag) :
 		psx_state(mconfig, type, tag),
 		m_gpu(*this, "gpu"),
-		m_znsec0(*this,"znsec0"),
-		m_znsec1(*this,"znsec1")
+		m_znsec0(*this,"maincpu:sio0:znsec0"),
+		m_znsec1(*this,"maincpu:sio0:znsec1"),
+		m_zndip(*this,"maincpu:sio0:zndip")
 	{
 	}
 
 	required_device<psxgpu_device> m_gpu;
 	required_device<znsec_device> m_znsec0;
 	required_device<znsec_device> m_znsec1;
+	required_device<zndip_device> m_zndip;
 	UINT32 m_n_znsecsel;
-	UINT32 m_b_znsecport;
-	int m_n_dip_bit;
-	int m_b_lastclock;
-	emu_timer *m_dip_timer;
 
 	size_t m_taitofx1_eeprom_size1;
 	UINT8 *m_taitofx1_eeprom1;
@@ -126,7 +125,6 @@ public:
 	DECLARE_MACHINE_RESET(coh1002v);
 	DECLARE_MACHINE_RESET(coh1002m);
 	INTERRUPT_GEN_MEMBER(qsound_interrupt);
-	TIMER_CALLBACK_MEMBER(dip_timer_fired);
 };
 
 INLINE void ATTR_PRINTF(3,4) verboselog( running_machine &machine, int n_level, const char *s_fmt, ... )
@@ -319,129 +317,17 @@ READ32_MEMBER(zn_state::znsecsel_r)
 	return m_n_znsecsel;
 }
 
-static void sio_znsec0_handler( running_machine &machine, int n_data )
-{
-	zn_state *state = machine.driver_data<zn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_CLOCK ) == 0 )
-	{
-		if( state->m_b_lastclock )
-		{
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, ( state->m_znsec0->step( ( n_data & PSX_SIO_OUT_DATA ) != 0 ) != 0 ) * PSX_SIO_IN_DATA );
-		}
-
-		state->m_b_lastclock = 0;
-	}
-	else
-	{
-		state->m_b_lastclock = 1;
-	}
-}
-
-static void sio_znsec1_handler( running_machine &machine, int n_data )
-{
-	zn_state *state = machine.driver_data<zn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_CLOCK ) == 0 )
-	{
-		if( state->m_b_lastclock )
-		{
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, ( state->m_znsec1->step( ( n_data & PSX_SIO_OUT_DATA ) != 0 ) != 0 ) * PSX_SIO_IN_DATA );
-		}
-
-		state->m_b_lastclock = 0;
-	}
-	else
-	{
-		state->m_b_lastclock = 1;
-	}
-}
-
-static void sio_pad_handler( running_machine &machine, int n_data )
-{
-	zn_state *state = machine.driver_data<zn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_DTR ) != 0 )
-	{
-		state->m_b_znsecport = 1;
-	}
-	else
-	{
-		state->m_b_znsecport = 0;
-	}
-
-	verboselog( machine, 2, "read pad %04x %04x %02x\n", state->m_n_znsecsel, state->m_b_znsecport, n_data );
-	psx_sio_input( machine, 0, PSX_SIO_IN_DATA | PSX_SIO_IN_DSR, PSX_SIO_IN_DATA | PSX_SIO_IN_DSR );
-}
-
-static void sio_dip_handler( running_machine &machine, int n_data )
-{
-	zn_state *state = machine.driver_data<zn_state>();
-
-	if( ( n_data & PSX_SIO_OUT_CLOCK ) == 0 )
-	{
-		if( state->m_b_lastclock )
-		{
-			int bit = ( ( state->ioport("DSW")->read() >> state->m_n_dip_bit ) & 1 );
-			verboselog( machine, 2, "read dip %02x -> %02x\n", n_data, bit * PSX_SIO_IN_DATA );
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, bit * PSX_SIO_IN_DATA );
-			state->m_n_dip_bit++;
-			state->m_n_dip_bit &= 7;
-		}
-		state->m_b_lastclock = 0;
-	}
-	else
-	{
-		state->m_b_lastclock = 1;
-	}
-}
-
 WRITE32_MEMBER(zn_state::znsecsel_w)
 {
 	COMBINE_DATA( &m_n_znsecsel );
 
 	m_znsec0->select( ( m_n_znsecsel >> 2 ) & 1 );
 	m_znsec1->select( ( m_n_znsecsel >> 3 ) & 1 );
-
-	if( ( m_n_znsecsel & 0x80 ) == 0 )
-	{
-		psx_sio_install_handler( machine(), 0, sio_pad_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-	}
-	else if( ( m_n_znsecsel & 0x08 ) == 0 )
-	{
-		psx_sio_install_handler( machine(), 0, sio_znsec1_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-	}
-	else if( ( m_n_znsecsel & 0x04 ) == 0 )
-	{
-		psx_sio_install_handler( machine(), 0, sio_znsec0_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-	}
-	else
-	{
-		m_n_dip_bit = 0;
-		m_b_lastclock = 1;
-
-		psx_sio_install_handler( machine(), 0, sio_dip_handler );
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, 0 );
-
-		m_dip_timer->adjust( downcast<cpu_device *>(&space.device())->cycles_to_attotime( 100 ), 1 );
-	}
+	m_zndip->select( ( m_n_znsecsel & 0x8c ) != 0x8c );
 
 	verboselog( machine(), 2, "znsecsel_w( %08x, %08x, %08x )\n", offset, data, mem_mask );
 }
 
-TIMER_CALLBACK_MEMBER(zn_state::dip_timer_fired)
-{
-	psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, param * PSX_SIO_IN_DSR );
-
-	if( param )
-	{
-		m_dip_timer->adjust( machine().device<cpu_device>( "maincpu" )->cycles_to_attotime(50 ) );
-	}
-}
-
 READ32_MEMBER(zn_state::boardconfig_r)
 {
 	/*
@@ -536,21 +422,11 @@ static void zn_driver_init( running_machine &machine )
 		{
 			state->m_znsec0->init( zn_config_table[ n_game ].p_n_mainsec );
 			state->m_znsec1->init( zn_config_table[ n_game ].p_n_gamesec );
-			psx_sio_install_handler( machine, 0, sio_pad_handler );
+//			psx_sio_install_handler( machine, 0, sio_pad_handler );
 			break;
 		}
 		n_game++;
 	}
-
-	state->m_dip_timer = machine.scheduler().timer_alloc( timer_expired_delegate(FUNC(zn_state::dip_timer_fired),state), NULL );
-}
-
-static void zn_machine_init( running_machine &machine )
-{
-	zn_state *state = machine.driver_data<zn_state>();
-
-	state->m_n_dip_bit = 0;
-	state->m_b_lastclock = 1;
 }
 
 static MACHINE_CONFIG_START( zn1_1mb_vram, zn_state )
@@ -558,8 +434,10 @@ static MACHINE_CONFIG_START( zn1_1mb_vram, zn_state )
 	MCFG_CPU_ADD( "maincpu", CXD8530CQ, XTAL_67_7376MHz )
 	MCFG_CPU_PROGRAM_MAP( zn_map)
 
-	MCFG_DEVICE_ADD("znsec0", ZNSEC, 0)
-	MCFG_DEVICE_ADD("znsec1", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:znsec0", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:znsec1", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:zndip", ZNDIP, 0)
+	MCFG_ZNDIP_DATA_HANDLER(IOPORT(":DSW"))
 
 	/* video hardware */
 	MCFG_PSXGPU_ADD( "maincpu", "gpu", CXD8561Q, 0x100000, XTAL_53_693175MHz )
@@ -583,8 +461,10 @@ static MACHINE_CONFIG_START( zn2, zn_state )
 	MCFG_CPU_ADD( "maincpu", CXD8661R, XTAL_100MHz )
 	MCFG_CPU_PROGRAM_MAP( zn_map)
 
-	MCFG_DEVICE_ADD("znsec0", ZNSEC, 0)
-	MCFG_DEVICE_ADD("znsec1", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:znsec0", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:znsec1", ZNSEC, 0)
+	MCFG_DEVICE_ADD("maincpu:sio0:zndip", ZNDIP, 0)
+	MCFG_ZNDIP_DATA_HANDLER(IOPORT(":DSW"))
 
 	/* video hardware */
 	MCFG_PSXGPU_ADD( "maincpu", "gpu", CXD8654Q, 0x200000, XTAL_53_693175MHz )
@@ -767,7 +647,6 @@ MACHINE_RESET_MEMBER(zn_state,coh1000c)
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* fixed game rom */
 	machine().root_device().membank( "bank2" )->set_base( machine().root_device().memregion( "user2" )->base() + 0x400000 ); /* banked game rom */
 	machine().root_device().membank( "bank3" )->set_base( machine().root_device().memregion( "user3" )->base() ); /* country rom */
-	zn_machine_init(machine());
 }
 
 static ADDRESS_MAP_START( qsound_map, AS_PROGRAM, 8, zn_state )
@@ -975,7 +854,6 @@ MACHINE_RESET_MEMBER(zn_state,coh3002c)
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* fixed game rom */
 	machine().root_device().membank( "bank2" )->set_base( machine().root_device().memregion( "user2" )->base() + 0x400000 ); /* banked game rom */
 	machine().root_device().membank( "bank3" )->set_base( machine().root_device().memregion( "user3" )->base() ); /* country rom */
-	zn_machine_init(machine());
 }
 
 static MACHINE_CONFIG_DERIVED( coh3002c, zn2 )
@@ -1260,7 +1138,6 @@ MACHINE_RESET_MEMBER(zn_state,coh1000ta)
 {
 	membank( "bank1" )->set_base( memregion( "user2" )->base() ); /* banked game rom */
 	membank( "bank2" )->set_base( m_taitofx1_eeprom1 );
-	zn_machine_init(machine());
 }
 
 static ADDRESS_MAP_START( fx1a_sound_map, AS_PROGRAM, 8, zn_state )
@@ -1350,11 +1227,9 @@ DRIVER_INIT_MEMBER(zn_state,coh1000tb)
 
 MACHINE_RESET_MEMBER(zn_state,coh1000tb)
 {
-
 	membank( "bank1" )->set_base( memregion( "user2" )->base() ); /* banked game rom */
 	membank( "bank2" )->set_base( m_taitofx1_eeprom1 );
 	membank( "bank3" )->set_base( m_taitofx1_eeprom2 );
-	zn_machine_init(machine());
 }
 
 static MACHINE_CONFIG_DERIVED( coh1000tb, zn1_2mb_vram )
@@ -1530,7 +1405,6 @@ DRIVER_INIT_MEMBER(zn_state,coh1000w)
 MACHINE_RESET_MEMBER(zn_state,coh1000w)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* fixed game rom */
-	zn_machine_init(machine());
 
 	machine().device("ide")->reset();
 }
@@ -1718,7 +1592,6 @@ DRIVER_INIT_MEMBER(zn_state,coh1002e)
 MACHINE_RESET_MEMBER(zn_state,coh1002e)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* banked game rom */
-	zn_machine_init(machine());
 }
 
 static ADDRESS_MAP_START( psarc_snd_map, AS_PROGRAM, 16, zn_state )
@@ -1862,8 +1735,6 @@ MACHINE_RESET_MEMBER(zn_state,bam2)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* fixed game rom */
 	machine().root_device().membank( "bank2" )->set_base( machine().root_device().memregion( "user2" )->base() + 0x400000 ); /* banked game rom */
-
-	zn_machine_init(machine());
 }
 
 static MACHINE_CONFIG_DERIVED( bam2, zn1_2mb_vram )
@@ -2190,7 +2061,6 @@ DRIVER_INIT_MEMBER(zn_state,coh1000a)
 MACHINE_RESET_MEMBER(zn_state,coh1000a)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* fixed game rom */
-	zn_machine_init(machine());
 	if( ( !strcmp( machine().system().name, "jdredd" ) ) ||
 		( !strcmp( machine().system().name, "jdreddb" ) ) )
 	{
@@ -2346,7 +2216,6 @@ DRIVER_INIT_MEMBER(zn_state,coh1001l)
 MACHINE_RESET_MEMBER(zn_state,coh1001l)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* banked rom */
-	zn_machine_init(machine());
 }
 
 static MACHINE_CONFIG_DERIVED( coh1001l, zn1_2mb_vram )
@@ -2390,7 +2259,6 @@ MACHINE_RESET_MEMBER(zn_state,coh1002v)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() ); /* fixed game rom */
 	machine().root_device().membank( "bank2" )->set_base( machine().root_device().memregion( "user3" )->base() ); /* banked rom */
-	zn_machine_init(machine());
 }
 
 static MACHINE_CONFIG_DERIVED( coh1002v, zn1_2mb_vram )
@@ -2592,7 +2460,6 @@ DRIVER_INIT_MEMBER(zn_state,coh1002m)
 MACHINE_RESET_MEMBER(zn_state,coh1002m)
 {
 	machine().root_device().membank( "bank1" )->set_base( machine().root_device().memregion( "user2" )->base() );
-	zn_machine_init(machine());
 }
 
 READ8_MEMBER(zn_state::cbaj_z80_latch_r)
diff --git a/src/mame/includes/psx.h b/src/mame/includes/psx.h
index 431463ca5ec..e199f63efa0 100644
--- a/src/mame/includes/psx.h
+++ b/src/mame/includes/psx.h
@@ -27,8 +27,6 @@ public:
 extern void psx_driver_init( running_machine &machine );
 DECLARE_WRITE32_HANDLER( psx_com_delay_w );
 DECLARE_READ32_HANDLER( psx_com_delay_r );
-extern void psx_sio_install_handler( running_machine &, int, psx_sio_handler );
-extern void psx_sio_input( running_machine &, int, int, int );
 
 #define PSX_H ( 1 )
 #endif
diff --git a/src/mame/machine/k573cass.c b/src/mame/machine/k573cass.c
new file mode 100644
index 00000000000..ea686db64a6
--- /dev/null
+++ b/src/mame/machine/k573cass.c
@@ -0,0 +1,19 @@
+#include "k573cass.h"
+
+const device_type KONAMI573CASSETTE = &device_creator<konami573cassette_device>;
+
+konami573cassette_device::konami573cassette_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+	psxsiodev_device(mconfig, KONAMI573CASSETTE, "KONAMI 573 CASSETTE", tag, owner, clock)
+{
+}
+
+void konami573cassette_device::device_start()
+{
+	psxsiodev_device::device_start();
+
+	data_out( PSX_SIO_IN_DSR, PSX_SIO_IN_DSR );
+}
+
+void konami573cassette_device::data_in( int data, int mask )
+{
+}
diff --git a/src/mame/machine/k573cass.h b/src/mame/machine/k573cass.h
new file mode 100644
index 00000000000..e85f7bb2c23
--- /dev/null
+++ b/src/mame/machine/k573cass.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#ifndef __K573CASS_H__
+#define __K573CASS_H__
+
+#include "cpu/psx/siodev.h"
+
+extern const device_type KONAMI573CASSETTE;
+
+class konami573cassette_device : public psxsiodev_device
+{
+public:
+	konami573cassette_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+
+protected:
+	void device_start();
+
+private:
+	virtual void data_in( int data, int mask );
+};
+
+#endif
diff --git a/src/mame/machine/psx.c b/src/mame/machine/psx.c
index 96880d7e51b..2bb3d12aae7 100644
--- a/src/mame/machine/psx.c
+++ b/src/mame/machine/psx.c
@@ -48,15 +48,3 @@ READ32_HANDLER( psx_com_delay_r )
 	verboselog( p_psx, 1, "psx_com_delay_r( %08x )\n", mem_mask );
 	return p_psx->n_com_delay;
 }
-
-/* SIO */
-
-void psx_sio_install_handler( running_machine &machine, int n_port, psx_sio_handler p_f_sio_handler )
-{
-	psxcpu_device::install_sio_handler( *machine.device("maincpu^"), "maincpu", n_port, p_f_sio_handler );
-}
-
-void psx_sio_input( running_machine &machine, int n_port, int n_mask, int n_data )
-{
-	psxcpu_device::sio_input( *machine.device("maincpu^"), "maincpu", n_port, n_mask, n_data );
-}
diff --git a/src/mame/machine/zndip.c b/src/mame/machine/zndip.c
new file mode 100644
index 00000000000..e3623f0def2
--- /dev/null
+++ b/src/mame/machine/zndip.c
@@ -0,0 +1,59 @@
+#include "zndip.h"
+
+const device_type ZNDIP = &device_creator<zndip_device>;
+
+zndip_device::zndip_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+	psxsiodev_device(mconfig, ZNDIP, "ZNDIP", tag, owner, clock),
+	m_data_handler(*this)
+{
+}
+
+void zndip_device::device_start()
+{
+	psxsiodev_device::device_start();
+
+	m_data_handler.resolve_safe( 0 );
+
+	m_dip_timer = timer_alloc( 0 );
+}
+
+void zndip_device::select(int select)
+{
+	if (m_select != select)
+	{
+		if (!select)
+		{
+			m_bit = 0;
+			m_dip_timer->adjust( attotime::from_usec( 100 ), 1 );
+		}
+		else
+		{
+			data_out(0, PSX_SIO_IN_DATA | PSX_SIO_IN_DSR);
+		}
+	
+		m_select = select;
+	}
+}
+
+void zndip_device::data_in( int data, int mask )
+{
+	if( !m_select && ( mask & PSX_SIO_OUT_CLOCK ) != 0 && ( data & PSX_SIO_OUT_CLOCK ) == 0)
+	{
+		int dip = m_data_handler();
+		int bit = ( ( dip >> m_bit ) & 1 );
+//		verboselog( machine, 2, "read dip %02x -> %02x\n", n_data, bit * PSX_SIO_IN_DATA );
+		data_out( bit * PSX_SIO_IN_DATA, PSX_SIO_IN_DATA );
+		m_bit++;
+		m_bit &= 7;
+	}
+}
+
+void zndip_device::device_timer(emu_timer &timer, device_timer_id tid, int param, void *ptr)
+{
+	data_out( param * PSX_SIO_IN_DSR, PSX_SIO_IN_DSR );
+
+	if( param )
+	{
+		m_dip_timer->adjust( attotime::from_usec( 50 ), 0 );
+	}
+}
diff --git a/src/mame/machine/zndip.h b/src/mame/machine/zndip.h
new file mode 100644
index 00000000000..790f127b286
--- /dev/null
+++ b/src/mame/machine/zndip.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#ifndef __ZNDIP_H__
+#define __ZNDIP_H__
+
+#include "cpu/psx/siodev.h"
+
+extern const device_type ZNDIP;
+
+#define MCFG_ZNDIP_DATA_HANDLER(_devcb) \
+	devcb = &zndip_device::set_data_handler(*device, DEVCB2_##_devcb); \
+
+class zndip_device : public psxsiodev_device
+{
+public:
+	zndip_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+
+	// static configuration helpers
+	template<class _Object> static devcb2_base &set_data_handler(device_t &device, _Object object) { return downcast<zndip_device &>(device).m_data_handler.set_callback(object); }
+
+	void select(int select);
+
+protected:
+	void device_start();
+	virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr);
+
+private:
+	virtual void data_in( int data, int mask );
+
+	devcb2_read8 m_data_handler;
+
+	int m_select;
+	UINT8 m_bit;
+	emu_timer *m_dip_timer;
+};
+
+#endif
diff --git a/src/mame/machine/znsec.c b/src/mame/machine/znsec.c
index 965bf7d55e6..17cd04c02ec 100644
--- a/src/mame/machine/znsec.c
+++ b/src/mame/machine/znsec.c
@@ -87,12 +87,14 @@
 const device_type ZNSEC = &device_creator<znsec_device>;
 
 znsec_device::znsec_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
-	device_t(mconfig, ZNSEC, "ZNSEC", tag, owner, clock)
+	psxsiodev_device(mconfig, ZNSEC, "ZNSEC", tag, owner, clock)
 {
 }
 
 void znsec_device::device_start()
 {
+	psxsiodev_device::device_start();
+
 	save_item(NAME(m_select));
 	save_item(NAME(m_state));
 	save_item(NAME(m_bit));
@@ -159,32 +161,41 @@ void znsec_device::init(const UINT8 *transform)
 
 void znsec_device::select(int select)
 {
-	if (m_select && !select)
+	if (m_select != select)
 	{
-		m_state = 0xfc;
-		m_bit = 0;
-	}
+		if (!select)
+		{
+			m_state = 0xfc;
+			m_bit = 0;
+		}
+		else
+		{
+			data_out(0, PSX_SIO_IN_DATA);
+		}
 	
-	m_select = select;
+		m_select = select;
+	}
 }
 
-UINT8 znsec_device::step(UINT8 input)
+void znsec_device::data_in( int data, int mask )
 {
-	UINT8 res;
 	static const UINT8 initial_sbox[8] = { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x7f };
 
-	if (m_bit==0)
+	if ( !m_select && (mask & PSX_SIO_OUT_CLOCK) != 0 && (data & PSX_SIO_OUT_CLOCK) == 0)
 	{
-		// Apply the initial sbox
-		apply_sbox(initial_sbox);
+		if (m_bit==0)
+		{
+			// Apply the initial sbox
+			apply_sbox(initial_sbox);
+		}
+
+		// Compute the output and change the state
+		data_out(((m_state >> m_bit) & 1) != 0 ? PSX_SIO_IN_DATA : 0, PSX_SIO_IN_DATA);
+
+		if((data & PSX_SIO_OUT_DATA)==0)
+			apply_bit_sbox(m_bit);
+
+		m_bit++;
+		m_bit&=7;
 	}
-
-	// Compute the output and change the state
-	res = (m_state >> m_bit) & 1;
-	if((input & 1)==0)
-		apply_bit_sbox(m_bit);
-
-	m_bit++;
-	m_bit&=7;
-	return res;
 }
diff --git a/src/mame/machine/znsec.h b/src/mame/machine/znsec.h
index 4a781a5a63f..b2ff99bf345 100644
--- a/src/mame/machine/znsec.h
+++ b/src/mame/machine/znsec.h
@@ -5,23 +5,24 @@
 #ifndef __ZNSEC_H__
 #define __ZNSEC_H__
 
-#include "emu.h"
+#include "cpu/psx/siodev.h"
 
 extern const device_type ZNSEC;
 
-class znsec_device : public device_t
+class znsec_device : public psxsiodev_device
 {
 public:
 	znsec_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
 
 	void init(const UINT8 *transform);
 	void select(int select);
-	UINT8 step(UINT8 input);
 
 protected:
 	void device_start();
 
 private:
+	virtual void data_in( int data, int mask );
+
 	UINT8 compute_sbox_coef(int sel, int bit);
 	void apply_bit_sbox(int sel);
 	void apply_sbox(const UINT8 *sbox);
diff --git a/src/mame/mame.mak b/src/mame/mame.mak
index f2aae180ba7..27559e2a688 100644
--- a/src/mame/mame.mak
+++ b/src/mame/mame.mak
@@ -920,7 +920,7 @@ $(MAMEOBJ)/konami.a: \
 	$(DRIVERS)/konamim2.o \
 	$(DRIVERS)/kontest.o \
 	$(DRIVERS)/konendev.o \
-	$(DRIVERS)/ksys573.o $(MACHINE)/zs01.o \
+	$(DRIVERS)/ksys573.o $(MACHINE)/k573cass.o $(MACHINE)/zs01.o \
 	$(DRIVERS)/labyrunr.o $(VIDEO)/labyrunr.o \
 	$(DRIVERS)/lethal.o $(VIDEO)/lethal.o \
 	$(DRIVERS)/mainevt.o $(VIDEO)/mainevt.o \
@@ -1366,7 +1366,7 @@ $(MAMEOBJ)/snk.a: \
 	$(DRIVERS)/snk68.o $(VIDEO)/snk68.o \
 
 $(MAMEOBJ)/sony.a: \
-	$(DRIVERS)/zn.o $(MACHINE)/znsec.o \
+	$(DRIVERS)/zn.o $(MACHINE)/zndip.o $(MACHINE)/znsec.o \
 	$(MACHINE)/psx.o
 
 $(MAMEOBJ)/stern.a: \
diff --git a/src/mess/drivers/psx.c b/src/mess/drivers/psx.c
index c36ce3784b8..ed6b8d6f16b 100644
--- a/src/mess/drivers/psx.c
+++ b/src/mess/drivers/psx.c
@@ -18,18 +18,7 @@
 #include "zlib.h"
 #include "machine/psxcd.h"
 #include "machine/psxcard.h"
-
-struct pad_t
-{
-	UINT8 n_shiftin;
-	UINT8 n_shiftout;
-	int n_bits;
-	int n_state;
-	int n_byte;
-	int b_lastclock;
-	int b_ack;
-};
-
+#include "machine/psxcport.h"
 
 class psx1_state : public psx_state
 {
@@ -39,7 +28,6 @@ public:
 
 	UINT8 *m_exe_buffer;
 	int m_exe_size;
-	pad_t m_pad[ 2 ];
 	int m_cd_param_p;
 	int m_cd_result_p;
 	int m_cd_result_c;
@@ -55,7 +43,6 @@ public:
 	DECLARE_DIRECT_UPDATE_MEMBER(psx_setopbase);
 	DECLARE_DRIVER_INIT(psx);
 	DECLARE_MACHINE_RESET(psx);
-	TIMER_CALLBACK_MEMBER(psx_pad_ack);
 };
 
 
@@ -476,191 +463,6 @@ static QUICKLOAD_LOAD( psx_exe_load )
 	return IMAGE_INIT_PASS;
 }
 
-/* PAD emulation */
-
-#define PAD_STATE_IDLE ( 0 )
-#define PAD_STATE_LISTEN ( 1 )
-#define PAD_STATE_ACTIVE ( 2 )
-#define PAD_STATE_READ ( 3 )
-#define PAD_STATE_UNLISTEN ( 4 )
-#define PAD_STATE_MEMCARD ( 5 )
-
-#define PAD_TYPE_STANDARD ( 4 )
-#define PAD_BYTES_STANDARD ( 2 )
-
-#define PAD_CMD_START ( 0x01 )
-#define PAD_CMD_READ  ( 0x42 ) /* B */
-
-#define PAD_DATA_OK   ( 0x5a ) /* Z */
-#define PAD_DATA_IDLE ( 0xff )
-
-TIMER_CALLBACK_MEMBER(psx1_state::psx_pad_ack)
-{
-	int n_port = param;
-	pad_t *pad = &m_pad[ n_port ];
-
-	if( pad->n_state != PAD_STATE_IDLE )
-	{
-		psx_sio_input( machine(), 0, PSX_SIO_IN_DSR, pad->b_ack * PSX_SIO_IN_DSR );
-		if( !pad->b_ack )
-		{
-			pad->b_ack = 1;
-			machine().scheduler().timer_set(attotime::from_usec( 2 ), timer_expired_delegate(FUNC(psx1_state::psx_pad_ack),this) , n_port);
-		}
-	}
-}
-
-static void psx_pad( running_machine &machine, int n_port, int n_data )
-{
-	psx1_state *state = machine.driver_data<psx1_state>();
-	pad_t *pad = &state->m_pad[ n_port ];
-	int b_sel;
-	int b_clock;
-	int b_data;
-	int b_ack;
-	int b_ready;
-	static const char *const portnames[] = { "IN0", "IN1", "IN2", "IN3" };
-	psxcard_device *psxcard = NULL;
-
-	if (n_port == 0)
-	{
-		psxcard = machine.device<psxcard_device>("card1");
-	}
-	else
-	{
-		psxcard = machine.device<psxcard_device>("card2");
-	}
-
-	b_sel = ( n_data & PSX_SIO_OUT_DTR ) / PSX_SIO_OUT_DTR;
-	b_clock = ( n_data & PSX_SIO_OUT_CLOCK ) / PSX_SIO_OUT_CLOCK;
-	b_data = ( n_data & PSX_SIO_OUT_DATA ) / PSX_SIO_OUT_DATA;
-	b_ready = 0;
-	b_ack = 0;
-
-	if( b_sel )
-	{
-		pad->n_state = PAD_STATE_IDLE;
-	}
-
-	switch( pad->n_state )
-	{
-	case PAD_STATE_LISTEN:
-	case PAD_STATE_ACTIVE:
-	case PAD_STATE_READ:
-	case PAD_STATE_MEMCARD:
-		if( pad->b_lastclock && !b_clock )
-		{
-			psx_sio_input( machine, 0, PSX_SIO_IN_DATA, ( pad->n_shiftout & 1 ) * PSX_SIO_IN_DATA );
-			pad->n_shiftout >>= 1;
-		}
-		if( !pad->b_lastclock && b_clock )
-		{
-			pad->n_shiftin >>= 1;
-			pad->n_shiftin |= b_data << 7;
-			pad->n_bits++;
-
-			if( pad->n_bits == 8 )
-			{
-				pad->n_bits = 0;
-				b_ready = 1;
-			}
-		}
-		break;
-	}
-
-	pad->b_lastclock = b_clock;
-
-	switch( pad->n_state )
-	{
-	case PAD_STATE_IDLE:
-		if( !b_sel )
-		{
-			pad->n_state = PAD_STATE_LISTEN;
-			pad->n_shiftout = PAD_DATA_IDLE;
-			pad->n_bits = 0;
-		}
-		break;
-	case PAD_STATE_LISTEN:
-		if( b_ready )
-		{
-			if( pad->n_shiftin == PAD_CMD_START )
-			{
-				pad->n_state = PAD_STATE_ACTIVE;
-				pad->n_shiftout = ( PAD_TYPE_STANDARD << 4 ) | ( PAD_BYTES_STANDARD >> 1 );
-				b_ack = 1;
-			}
-			else if( psxcard->transfer(pad->n_shiftin, &pad->n_shiftout) )
-			{
-				pad->n_state = PAD_STATE_MEMCARD;
-				b_ack = 1;
-			}
-			else
-			{
-				pad->n_state = PAD_STATE_UNLISTEN;
-			}
-		}
-		break;
-	case PAD_STATE_MEMCARD:
-		if( b_ready )
-		{
-			if( psxcard->transfer(pad->n_shiftin, &pad->n_shiftout) )
-			{
-				b_ack = 1;
-			}
-			else
-			{
-				b_ack = 0;
-				pad->n_state = PAD_STATE_IDLE;
-			}
-		}
-		break;
-	case PAD_STATE_ACTIVE:
-		if( b_ready )
-		{
-			if( pad->n_shiftin == PAD_CMD_READ )
-			{
-				pad->n_state = PAD_STATE_READ;
-				pad->n_shiftout = PAD_DATA_OK;
-				pad->n_byte = 0;
-				b_ack = 1;
-			}
-			else
-			{
-				pad->n_state = PAD_STATE_UNLISTEN;
-			}
-		}
-		break;
-	case PAD_STATE_READ:
-		if( b_ready )
-		{
-			if( pad->n_byte < PAD_BYTES_STANDARD )
-			{
-				pad->n_shiftout = machine.root_device().ioport(portnames[pad->n_byte + ( n_port * PAD_BYTES_STANDARD )])->read();
-				pad->n_byte++;
-				b_ack = 1;
-			}
-			else
-			{
-				pad->n_state = PAD_STATE_LISTEN;
-			}
-		}
-		break;
-	}
-
-	if( b_ack )
-	{
-		pad->b_ack = 0;
-		machine.scheduler().timer_set(attotime::from_usec( 10 ), timer_expired_delegate(FUNC(psx1_state::psx_pad_ack),state), n_port);
-	}
-}
-
-static void psx_sio0( running_machine &machine, int n_data )
-{
-	/* todo: raise data & ack when nothing is driving it low */
-	psx_pad( machine, 0, n_data );
-	psx_pad( machine, 1, n_data ^ PSX_SIO_OUT_DTR );
-}
-
 /* ----------------------------------------------------------------------- */
 
 static void cd_dma_read( psxcd_device *psxcd, UINT32 n_address, INT32 n_size )
@@ -701,12 +503,6 @@ static ADDRESS_MAP_START( psx_map, AS_PROGRAM, 32, psx1_state )
 	AM_RANGE(0xfffe0130, 0xfffe0133) AM_WRITENOP
 ADDRESS_MAP_END
 
-
-MACHINE_RESET_MEMBER(psx1_state,psx)
-{
-	psx_sio_install_handler( machine(), 0, psx_sio0 );
-}
-
 DRIVER_INIT_MEMBER(psx1_state,psx)
 {
 	psx_driver_init(machine());
@@ -765,7 +561,7 @@ static MACHINE_CONFIG_START( psxntsc, psx1_state )
 	MCFG_CPU_ADD( "maincpu", CXD8530CQ, XTAL_67_7376MHz )
 	MCFG_CPU_PROGRAM_MAP( psx_map )
 
-	MCFG_MACHINE_RESET_OVERRIDE(psx1_state, psx )
+	MCFG_DEVICE_ADD("maincpu:sio0:controllers", PSXCONTROLLERPORTS, 0)
 
 	/* video hardware */
 	MCFG_PSXGPU_ADD( "maincpu", "gpu", CXD8561Q, 0x100000, XTAL_53_693175MHz )
@@ -796,8 +592,6 @@ static MACHINE_CONFIG_START( psxpal, psx1_state )
 	MCFG_CPU_ADD( "maincpu", CXD8530AQ, XTAL_67_7376MHz )
 	MCFG_CPU_PROGRAM_MAP( psx_map)
 
-	MCFG_MACHINE_RESET_OVERRIDE(psx1_state, psx )
-
 	/* video hardware */
 	/* TODO: visible area and refresh rate */
 	MCFG_PSXGPU_ADD( "maincpu", "gpu", CXD8561Q, 0x100000, XTAL_53_693175MHz )
diff --git a/src/mess/machine/psxcport.c b/src/mess/machine/psxcport.c
new file mode 100644
index 00000000000..482e44ea58f
--- /dev/null
+++ b/src/mess/machine/psxcport.c
@@ -0,0 +1,201 @@
+/* PAD emulation */
+
+#include "psxcport.h"
+#include "machine/psxcard.h"
+
+#define PAD_STATE_IDLE ( 0 )
+#define PAD_STATE_LISTEN ( 1 )
+#define PAD_STATE_ACTIVE ( 2 )
+#define PAD_STATE_READ ( 3 )
+#define PAD_STATE_UNLISTEN ( 4 )
+#define PAD_STATE_MEMCARD ( 5 )
+
+#define PAD_TYPE_STANDARD ( 4 )
+#define PAD_BYTES_STANDARD ( 2 )
+
+#define PAD_CMD_START ( 0x01 )
+#define PAD_CMD_READ  ( 0x42 ) /* B */
+
+#define PAD_DATA_OK   ( 0x5a ) /* Z */
+#define PAD_DATA_IDLE ( 0xff )
+
+const device_type PSXCONTROLLERPORTS = &device_creator<psxcontrollerports_device>;
+
+psxcontrollerports_device::psxcontrollerports_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+	psxsiodev_device(mconfig, PSXCONTROLLERPORTS, "PSXCONTROLLERPORTS", tag, owner, clock)
+{
+}
+
+void psxcontrollerports_device::device_start()
+{
+	psxsiodev_device::device_start();
+
+	m_ack_timer = timer_alloc( 0 );
+}
+
+void psxcontrollerports_device::device_timer(emu_timer &timer, device_timer_id tid, int param, void *ptr)
+{
+	int n_port = param;
+	pad_t *pad = &m_pad[ n_port ];
+
+	if( pad->n_state != PAD_STATE_IDLE )
+	{
+		data_out( pad->b_ack * PSX_SIO_IN_DSR, PSX_SIO_IN_DSR );
+
+		if( !pad->b_ack )
+		{
+			pad->b_ack = 1;
+			m_ack_timer->adjust( attotime::from_usec( 2 ), n_port );
+		}
+	}
+}
+
+void psxcontrollerports_device::psx_pad( int n_port, int n_data )
+{
+	pad_t *pad = &m_pad[ n_port ];
+	int b_sel;
+	int b_clock;
+	int b_data;
+	int b_ack;
+	int b_ready;
+	static const char *const portnames[] = { ":IN0", ":IN1", ":IN2", ":IN3" };
+	psxcard_device *psxcard = NULL;
+
+	if (n_port == 0)
+	{
+		psxcard = machine().device<psxcard_device>(":card1");
+	}
+	else
+	{
+		psxcard = machine().device<psxcard_device>(":card2");
+	}
+
+	b_sel = ( n_data & PSX_SIO_OUT_DTR ) / PSX_SIO_OUT_DTR;
+	b_clock = ( n_data & PSX_SIO_OUT_CLOCK ) / PSX_SIO_OUT_CLOCK;
+	b_data = ( n_data & PSX_SIO_OUT_DATA ) / PSX_SIO_OUT_DATA;
+	b_ready = 0;
+	b_ack = 0;
+
+	if( b_sel )
+	{
+		pad->n_state = PAD_STATE_IDLE;
+	}
+
+	switch( pad->n_state )
+	{
+	case PAD_STATE_LISTEN:
+	case PAD_STATE_ACTIVE:
+	case PAD_STATE_READ:
+	case PAD_STATE_MEMCARD:
+		if( pad->b_lastclock && !b_clock )
+		{
+			data_out( ( pad->n_shiftout & 1 ) * PSX_SIO_IN_DATA, PSX_SIO_IN_DATA );
+			pad->n_shiftout >>= 1;
+		}
+		if( !pad->b_lastclock && b_clock )
+		{
+			pad->n_shiftin >>= 1;
+			pad->n_shiftin |= b_data << 7;
+			pad->n_bits++;
+
+			if( pad->n_bits == 8 )
+			{
+				pad->n_bits = 0;
+				b_ready = 1;
+			}
+		}
+		break;
+	}
+
+	pad->b_lastclock = b_clock;
+
+	switch( pad->n_state )
+	{
+	case PAD_STATE_IDLE:
+		if( !b_sel )
+		{
+			pad->n_state = PAD_STATE_LISTEN;
+			pad->n_shiftout = PAD_DATA_IDLE;
+			pad->n_bits = 0;
+		}
+		break;
+	case PAD_STATE_LISTEN:
+		if( b_ready )
+		{
+			if( pad->n_shiftin == PAD_CMD_START )
+			{
+				pad->n_state = PAD_STATE_ACTIVE;
+				pad->n_shiftout = ( PAD_TYPE_STANDARD << 4 ) | ( PAD_BYTES_STANDARD >> 1 );
+				b_ack = 1;
+			}
+			else if( psxcard->transfer(pad->n_shiftin, &pad->n_shiftout) )
+			{
+				pad->n_state = PAD_STATE_MEMCARD;
+				b_ack = 1;
+			}
+			else
+			{
+				pad->n_state = PAD_STATE_UNLISTEN;
+			}
+		}
+		break;
+	case PAD_STATE_MEMCARD:
+		if( b_ready )
+		{
+			if( psxcard->transfer(pad->n_shiftin, &pad->n_shiftout) )
+			{
+				b_ack = 1;
+			}
+			else
+			{
+				b_ack = 0;
+				pad->n_state = PAD_STATE_IDLE;
+			}
+		}
+		break;
+	case PAD_STATE_ACTIVE:
+		if( b_ready )
+		{
+			if( pad->n_shiftin == PAD_CMD_READ )
+			{
+				pad->n_state = PAD_STATE_READ;
+				pad->n_shiftout = PAD_DATA_OK;
+				pad->n_byte = 0;
+				b_ack = 1;
+			}
+			else
+			{
+				pad->n_state = PAD_STATE_UNLISTEN;
+			}
+		}
+		break;
+	case PAD_STATE_READ:
+		if( b_ready )
+		{
+			if( pad->n_byte < PAD_BYTES_STANDARD )
+			{
+				pad->n_shiftout = ioport(portnames[pad->n_byte + ( n_port * PAD_BYTES_STANDARD )])->read();
+				pad->n_byte++;
+				b_ack = 1;
+			}
+			else
+			{
+				pad->n_state = PAD_STATE_LISTEN;
+			}
+		}
+		break;
+	}
+
+	if( b_ack )
+	{
+		pad->b_ack = 0;
+		m_ack_timer->adjust( attotime::from_usec( 10 ), n_port );
+	}
+}
+
+void psxcontrollerports_device::data_in( int data, int mask )
+{
+	/* todo: raise data & ack when nothing is driving it low */
+	psx_pad( 0, data );
+	psx_pad( 1, data ^ PSX_SIO_OUT_DTR );
+}
diff --git a/src/mess/machine/psxcport.h b/src/mess/machine/psxcport.h
new file mode 100644
index 00000000000..7ed4330f638
--- /dev/null
+++ b/src/mess/machine/psxcport.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#ifndef __PSXCPORT_H__
+#define __PSXCPORT_H__
+
+#include "cpu/psx/siodev.h"
+
+extern const device_type PSXCONTROLLERPORTS;
+
+struct pad_t
+{
+	UINT8 n_shiftin;
+	UINT8 n_shiftout;
+	int n_bits;
+	int n_state;
+	int n_byte;
+	int b_lastclock;
+	int b_ack;
+};
+
+class psxcontrollerports_device : public psxsiodev_device
+{
+public:
+	psxcontrollerports_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+
+protected:
+	void device_start();
+	virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr);
+
+private:
+	void psx_pad( int n_port, int n_data );
+	virtual void data_in( int data, int mask );
+
+	pad_t m_pad[ 2 ];
+	emu_timer *m_ack_timer;
+};
+
+#endif
diff --git a/src/mess/mess.mak b/src/mess/mess.mak
index 2837e1b0e27..a9d38031296 100644
--- a/src/mess/mess.mak
+++ b/src/mess/mess.mak
@@ -1668,6 +1668,7 @@ $(MESSOBJ)/snk.a:				\
 
 $(MESSOBJ)/sony.a:				\
 	$(MESS_DRIVERS)/psx.o		\
+	$(MESS_MACHINE)/psxcport.o	\
 	$(MESS_MACHINE)/psxcd.o		\
 	$(MESS_MACHINE)/psxcddrv.o	\
 	$(MESS_MACHINE)/psxcard.o	\