diff --git a/scripts/src/bus.lua b/scripts/src/bus.lua
index d6e3a9311fa..60dbdcaed71 100644
--- a/scripts/src/bus.lua
+++ b/scripts/src/bus.lua
@@ -4096,6 +4096,8 @@ if (BUSES["HP9845_IO"]~=null) then
 		MAME_DIR .. "src/devices/bus/hp9845_io/98034.h",
 		MAME_DIR .. "src/devices/bus/hp9845_io/98035.cpp",
 		MAME_DIR .. "src/devices/bus/hp9845_io/98035.h",
+		MAME_DIR .. "src/devices/bus/hp9845_io/98036.cpp",
+		MAME_DIR .. "src/devices/bus/hp9845_io/98036.h",
 		MAME_DIR .. "src/devices/bus/hp9845_io/98046.cpp",
 		MAME_DIR .. "src/devices/bus/hp9845_io/98046.h",
 		MAME_DIR .. "src/devices/bus/hp9845_io/hp9885.cpp",
diff --git a/src/devices/bus/hp9845_io/98036.cpp b/src/devices/bus/hp9845_io/98036.cpp
new file mode 100644
index 00000000000..4d0f5011118
--- /dev/null
+++ b/src/devices/bus/hp9845_io/98036.cpp
@@ -0,0 +1,505 @@
+// license:BSD-3-Clause
+// copyright-holders: F. Ulivi
+/*********************************************************************
+
+    98036.cpp
+
+    98036 module (RS232 interface)
+
+    Main reference for this module:
+    HP, 98036A Serial I/O interface installation & service manual
+
+*********************************************************************/
+
+#include "98036.h"
+
+// Debugging
+#define VERBOSE 0
+#include "logmacro.h"
+
+// Bit manipulation
+namespace {
+	template<typename T> constexpr T BIT_MASK(unsigned n)
+	{
+		return (T)1U << n;
+	}
+
+	template<typename T> void BIT_SET(T& w , unsigned n)
+	{
+		w |= BIT_MASK<T>(n);
+	}
+}
+
+// device type definitions
+DEFINE_DEVICE_TYPE(HP98036_IO_CARD, hp98036_io_card_device, "hp98036" , "HP98036 card")
+
+hp98036_io_card_device::hp98036_io_card_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+: device_t(mconfig, HP98036_IO_CARD, tag, owner, clock)
+	, device_hp9845_io_interface(mconfig, *this)
+	, m_uart(*this , "uart")
+	, m_clock_gen(*this , "clock_gen")
+	, m_rs232(*this , "rs232")
+	, m_s1_input(*this , "s1")
+	, m_s2_input(*this , "s2")
+	, m_s3_input(*this , "s3")
+	, m_jumper_input(*this , "jumper")
+	, m_loopback_en(*this , "loop")
+{
+}
+
+hp98036_io_card_device::~hp98036_io_card_device()
+{
+}
+
+uint16_t hp98036_io_card_device::reg_r(address_space &space, offs_t offset)
+{
+	uint16_t res = 0;
+
+	switch (offset) {
+	case 0:
+		// R4IN
+		m_r4_dir = false;
+		res = m_r4in_data;
+		break;
+
+	case 1:
+		// R5IN
+		if (m_tx_int_en) {
+			BIT_SET(res, 0);
+		}
+		if (m_rx_int_en) {
+			BIT_SET(res, 1);
+		}
+		BIT_SET(res, 4);
+		if (m_int_en) {
+			BIT_SET(res, 7);
+		}
+		break;
+
+	case 2:
+		// R6IN
+		// Bits 3&4: jumpers
+		res = (m_jumper_input->read() & 3) << 3;
+		if (m_loopback) {
+			res |= m_lineout;
+		} else {
+			if (!m_rs232->dcd_r()) {
+				BIT_SET(res, 0);
+			}
+			if (!m_rs232->ri_r()) {
+				BIT_SET(res, 1);
+			}
+			// Bit 2: secondary CD, always 0
+		}
+		BIT_SET(res, 5);
+		BIT_SET(res, 6);
+		BIT_SET(res, 7);
+		break;
+
+	default:
+		logerror("Unmapped read @%u\n" , offset);
+		break;
+	}
+
+	LOG("RD R%u=%02x\n" , offset + 4 , res);
+	return res;
+}
+
+void hp98036_io_card_device::reg_w(address_space &space, offs_t offset, uint16_t data)
+{
+	LOG("WR R%u=%02x\n" , offset + 4 , data);
+
+	switch (offset) {
+	case 0:
+		// R4OUT
+		m_r4_dir = true;
+		m_wrrq = true;
+		m_r4out_data = data;
+		uart_wr();
+		update_flg();
+		break;
+
+	case 1:
+		// R5OUT
+		m_uart_cmd = BIT(data , 0);
+		m_tx_int_en = BIT(data , 1);
+		m_rx_int_en = BIT(data , 2);
+		m_int_en = BIT(data , 7);
+		if (BIT(data , 5)) {
+			int_reset();
+		} else {
+			uart_rd();
+			uart_wr();
+			update_irq();
+			update_flg();
+		}
+		break;
+
+	case 2:
+		// R6OUT
+		m_half_baud = BIT(data , 4);
+		m_lineout = data & 7;
+		break;
+
+	case 3:
+		// R7OUT
+		if (!m_r4_dir) {
+			m_rdrq = true;
+			uart_rd();
+			update_irq();
+			update_flg();
+		}
+		break;
+
+	default:
+		logerror("Unmapped write @%u\n" , offset);
+		break;
+	}
+}
+
+void hp98036_io_card_device::device_add_mconfig(machine_config &config)
+{
+	I8251(config , m_uart , 0);
+	m_uart->txd_handler().set(FUNC(hp98036_io_card_device::txd_w));
+	m_uart->dtr_handler().set(FUNC(hp98036_io_card_device::dtr_w));
+	m_uart->rts_handler().set(FUNC(hp98036_io_card_device::rts_w));
+	m_uart->rxrdy_handler().set(FUNC(hp98036_io_card_device::rxrdy_w));
+	m_uart->txrdy_handler().set(FUNC(hp98036_io_card_device::txrdy_w));
+
+	MC14411(config , m_clock_gen , 1.8432_MHz_XTAL);
+	m_clock_gen->out_f<1>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<3>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<5>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<6>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<7>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<8>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<9>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<11>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<13>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<14>().set(FUNC(hp98036_io_card_device::bit_rate_clock));
+	m_clock_gen->out_f<12>().set(FUNC(hp98036_io_card_device::slow_clock));
+
+	RS232_PORT(config , m_rs232 , default_rs232_devices , nullptr);
+	m_rs232->rxd_handler().set(FUNC(hp98036_io_card_device::rxd_w));
+	m_rs232->dsr_handler().set(FUNC(hp98036_io_card_device::dsr_w));
+	m_rs232->cts_handler().set(FUNC(hp98036_io_card_device::cts_w));
+}
+
+static INPUT_PORTS_START(hp98036_port)
+	PORT_HP9845_IO_SC(11)
+
+	PORT_START("s1")
+	PORT_DIPNAME(3 , 3 , "Clock factor")
+	PORT_DIPLOCATION("S1:1,2")
+	PORT_DIPSETTING(1 , "x1")
+	PORT_DIPSETTING(2 , "x16")
+	PORT_DIPSETTING(3 , "x64")
+	PORT_DIPNAME(0x0c , 0x0c , "Character length")
+	PORT_DIPLOCATION("S1:3,4")
+	PORT_DIPSETTING(0x00 , "5")
+	PORT_DIPSETTING(0x04 , "6")
+	PORT_DIPSETTING(0x08 , "7")
+	PORT_DIPSETTING(0x0c , "8")
+	PORT_DIPNAME(0x10 , 0 , "Parity enable")
+	PORT_DIPLOCATION("S1:5")
+	PORT_DIPSETTING(0x00 , DEF_STR(Off))
+	PORT_DIPSETTING(0x10 , DEF_STR(On))
+	PORT_DIPNAME(0x20 , 0 , "Parity")
+	PORT_DIPLOCATION("S1:6")
+	PORT_DIPSETTING(0x00 , "Odd")
+	PORT_DIPSETTING(0x20 , "Even")
+	PORT_DIPNAME(0xc0 , 0xc0 , "Stop bits")
+	PORT_DIPLOCATION("S1:7,8")
+	PORT_DIPSETTING(0x40 , "1")
+	PORT_DIPSETTING(0x80 , "1.5")
+	PORT_DIPSETTING(0xc0 , "2")
+
+	PORT_START("s2")
+	PORT_DIPNAME(1 , 1 , "CTS")
+	PORT_DIPLOCATION("S2:1")
+	PORT_DIPSETTING(0 , "Device controlled")
+	PORT_DIPSETTING(1 , "Always active")
+
+	PORT_START("s3")
+	PORT_CONFNAME(0xf , 6 , "Baud rate")
+	PORT_CONFSETTING(0 , "9600")
+	PORT_CONFSETTING(1 , "4800")
+	PORT_CONFSETTING(2 , "2400")
+	PORT_CONFSETTING(3 , "1800")
+	PORT_CONFSETTING(4 , "1200")
+	PORT_CONFSETTING(5 , "600")
+	PORT_CONFSETTING(6 , "300")
+	PORT_CONFSETTING(7 , "150")
+	PORT_CONFSETTING(8 , "110")
+	PORT_CONFSETTING(9 , "75")
+
+	PORT_START("jumper")
+	PORT_CONFNAME(1 , 0 , "J1")
+	PORT_CONFSETTING(0 , DEF_STR(Off))
+	PORT_CONFSETTING(1 , DEF_STR(On))
+	PORT_CONFNAME(2 , 0 , "J2")
+	PORT_CONFSETTING(0 , DEF_STR(Off))
+	PORT_CONFSETTING(2 , DEF_STR(On))
+
+	PORT_START("loop")
+	PORT_CONFNAME(1 , 0 , "Test loopback")
+	PORT_CONFSETTING(0 , DEF_STR(Off))
+	PORT_CONFSETTING(1 , DEF_STR(On))
+INPUT_PORTS_END
+
+ioport_constructor hp98036_io_card_device::device_input_ports() const
+{
+	return INPUT_PORTS_NAME(hp98036_port);
+}
+
+void hp98036_io_card_device::device_start()
+{
+	save_item(NAME(m_init_state));
+	save_item(NAME(m_irq));
+	save_item(NAME(m_int_en));
+	save_item(NAME(m_tx_int_en));
+	save_item(NAME(m_rx_int_en));
+	save_item(NAME(m_txrdy));
+	save_item(NAME(m_rxrdy));
+	save_item(NAME(m_wrrq));
+	save_item(NAME(m_rdrq));
+	save_item(NAME(m_uart_cmd));
+	save_item(NAME(m_uart_wr_mode));
+	save_item(NAME(m_flg));
+	save_item(NAME(m_half_baud));
+	save_item(NAME(m_baud_div));
+	save_item(NAME(m_r4_dir));
+	save_item(NAME(m_r4in_data));
+	save_item(NAME(m_r4out_data));
+	save_item(NAME(m_lineout));
+}
+
+void hp98036_io_card_device::device_reset()
+{
+	sts_w(true);
+
+	ioport_value baud_sel = m_s3_input->read();
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F1 , baud_sel == 0);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F3 , baud_sel == 1);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F5 , baud_sel == 2);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F6 , baud_sel == 3);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F7 , baud_sel == 4);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F8 , baud_sel == 5);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F9 , baud_sel == 6);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F11 , baud_sel == 7);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F13 , baud_sel == 8);
+	m_clock_gen->timer_enable(mc14411_device::TIMER_F14 , baud_sel == 9);
+
+	m_loopback = m_loopback_en->read() != 0;
+
+	if (!m_loopback && BIT(m_s2_input->read() , 0)) {
+		m_uart->write_cts(0);
+	}
+
+	int_reset();
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::bit_rate_clock)
+{
+	if (m_half_baud) {
+		if (state) {
+			m_baud_div = !m_baud_div;
+			m_uart->write_txc(m_baud_div);
+			m_uart->write_rxc(m_baud_div);
+		}
+	} else {
+		m_uart->write_txc(state);
+		m_uart->write_rxc(state);
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::slow_clock)
+{
+	switch (m_init_state) {
+	case 0:
+		// Reset
+		if (state) {
+			m_init_state++;
+		}
+		break;
+
+	case 1:
+		// Write mode word
+		if (state) {
+			m_init_state++;
+		} else {
+			write_uart(true , uint8_t(m_s1_input->read()));
+		}
+		break;
+
+	case 2:
+		// Write default control word
+		if (state) {
+			m_init_state++;
+			update_flg();
+		} else {
+			write_uart(true , 0x05);
+		}
+		break;
+
+	default:
+		break;
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::txd_w)
+{
+	if (m_loopback) {
+		m_uart->write_rxd(state);
+	} else {
+		m_rs232->write_txd(state);
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::dtr_w)
+{
+	if (m_loopback) {
+		m_uart->write_dsr(state);
+	} else {
+		m_rs232->write_dtr(state);
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::rts_w)
+{
+	if (m_loopback) {
+		m_uart->write_cts(state);
+	} else {
+		m_rs232->write_rts(state);
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::txrdy_w)
+{
+	if (m_txrdy != state) {
+		m_txrdy = state;
+		LOG("txrdy %d\n" , m_txrdy);
+		uart_wr();
+		update_irq();
+		update_flg();
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::rxrdy_w)
+{
+	if (m_rxrdy != state) {
+		m_rxrdy = state;
+		LOG("rxrdy %d\n" , m_rxrdy);
+		uart_rd();
+		update_irq();
+		update_flg();
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::rxd_w)
+{
+	if (!m_loopback) {
+		m_uart->write_rxd(state);
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::dsr_w)
+{
+	if (!m_loopback) {
+		m_uart->write_dsr(state);
+	}
+}
+
+WRITE_LINE_MEMBER(hp98036_io_card_device::cts_w)
+{
+	if (!m_loopback && !BIT(m_s2_input->read() , 0)) {
+		m_uart->write_cts(state);
+	}
+}
+
+void hp98036_io_card_device::int_reset()
+{
+	m_init_state = 0;
+	m_r4in_data = 0;
+	m_r4out_data = 0;
+	m_wrrq = false;
+	m_rdrq = false;
+	m_int_en = false;
+	m_tx_int_en = false;
+	m_rx_int_en = false;
+	m_uart_cmd = false;
+	m_uart_wr_mode = true;
+	m_half_baud = false;
+	m_lineout = 0;
+	m_clock_gen->rate_select_w(0);
+	m_flg = true; // Ensure update in update_flg
+	update_flg();
+	m_irq = true; // Ensure update in update_irq
+	update_irq();
+	m_uart->reset();
+}
+
+void hp98036_io_card_device::update_flg()
+{
+	bool new_flg = (m_init_state == 3) && (!m_wrrq || m_tx_int_en) && (!m_rdrq || m_rx_int_en);
+
+	if (m_flg != new_flg) {
+		m_flg = new_flg;
+		LOG("FLG %d\n" , m_flg);
+		flg_w(m_flg);
+	}
+}
+
+void hp98036_io_card_device::update_irq()
+{
+	bool new_irq = m_int_en && ((m_tx_int_en && m_txrdy) || (m_rx_int_en && !m_rdrq));
+
+	if (m_irq != new_irq) {
+		m_irq = new_irq;
+		LOG("IRQ %d\n" , m_irq);
+		irq_w(m_irq);
+	}
+}
+
+void hp98036_io_card_device::uart_rd()
+{
+	if (m_rdrq && (m_rxrdy || m_uart_cmd)) {
+		m_rdrq = false;
+		m_r4in_data = m_uart->read(m_uart_cmd);
+		LOG("uart rd%d=%02x\n" , m_uart_cmd ,  m_r4in_data);
+		update_flg();
+	}
+}
+
+void hp98036_io_card_device::uart_wr()
+{
+	if (m_wrrq && (m_txrdy || m_uart_cmd)) {
+		m_wrrq = false;
+		write_uart(m_uart_cmd , m_r4out_data);
+		update_flg();
+	}
+}
+
+void hp98036_io_card_device::write_uart(bool cmd , uint8_t data)
+{
+	if (cmd && m_uart_wr_mode) {
+		// Capture bits 1 & 0 of mode word (clock factor) and
+		// adjust rate selection in clock generator
+		// Mode word    RSB/RSA Factor
+		// 0 0          0 0     -- INVALID --
+		// 0 1          0 0     x1
+		// 1 0          1 0     x16
+		// 1 1          1 1     x64
+		m_clock_gen->rate_select_w((BIT(data , 1) ? mc14411_device::RSB : 0) | ((BIT(data , 1) && BIT(data , 0)) ? mc14411_device::RSA : 0));
+		LOG("RS %u\n" , data & 3);
+	}
+	if (cmd) {
+		if (BIT(data , 6)) {
+			m_uart_wr_mode = !m_uart_wr_mode;
+		} else {
+			m_uart_wr_mode = false;
+		}
+	}
+	LOG("uart wr%d=%02x\n" , cmd , data);
+	m_uart->write(cmd , data);
+}
diff --git a/src/devices/bus/hp9845_io/98036.h b/src/devices/bus/hp9845_io/98036.h
new file mode 100644
index 00000000000..c73d32652a5
--- /dev/null
+++ b/src/devices/bus/hp9845_io/98036.h
@@ -0,0 +1,96 @@
+// license:BSD-3-Clause
+// copyright-holders: F. Ulivi
+/*********************************************************************
+
+    98036.h
+
+    98036 module (RS232 interface)
+
+*********************************************************************/
+
+#ifndef MAME_BUS_HP9845_IO_98036_H
+#define MAME_BUS_HP9845_IO_98036_H
+
+#pragma once
+
+#include "hp9845_io.h"
+#include "machine/i8251.h"
+#include "machine/mc14411.h"
+#include "bus/rs232/rs232.h"
+
+class hp98036_io_card_device : public device_t, public device_hp9845_io_interface
+{
+public:
+	// construction/destruction
+	hp98036_io_card_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+	virtual ~hp98036_io_card_device();
+
+	virtual uint16_t reg_r(address_space &space, offs_t offset) override;
+	virtual void reg_w(address_space &space, offs_t offset, uint16_t data) override;
+
+protected:
+	// device-level overrides
+	virtual void device_add_mconfig(machine_config &config) override;
+	virtual ioport_constructor device_input_ports() const override;
+	virtual void device_start() override;
+	virtual void device_reset() override;
+
+private:
+	required_device<i8251_device> m_uart;
+	required_device<mc14411_device> m_clock_gen;
+	required_device<rs232_port_device> m_rs232;
+	required_ioport m_s1_input;
+	required_ioport m_s2_input;
+	required_ioport m_s3_input;
+	required_ioport m_jumper_input;
+	required_ioport m_loopback_en;
+
+	DECLARE_WRITE_LINE_MEMBER(bit_rate_clock);
+	DECLARE_WRITE_LINE_MEMBER(slow_clock);
+	DECLARE_WRITE_LINE_MEMBER(txd_w);
+	DECLARE_WRITE_LINE_MEMBER(dtr_w);
+	DECLARE_WRITE_LINE_MEMBER(rts_w);
+	DECLARE_WRITE_LINE_MEMBER(txrdy_w);
+	DECLARE_WRITE_LINE_MEMBER(rxrdy_w);
+	DECLARE_WRITE_LINE_MEMBER(rxd_w);
+	DECLARE_WRITE_LINE_MEMBER(dsr_w);
+	DECLARE_WRITE_LINE_MEMBER(cts_w);
+
+	// State of initialization FSM
+	// State U11A-Q U11B-Q
+	// 0     0      0
+	// 1     1      0      Load mode word
+	// 2     1      1      Load control word
+	// 3     0      1      Done
+	uint8_t m_init_state;
+	bool m_irq;         // U9-2
+	bool m_int_en;      // U10-2
+	bool m_tx_int_en;   // U10-10
+	bool m_rx_int_en;   // U10-7
+	bool m_txrdy;       // U31-15
+	bool m_rxrdy;       // U31-14
+	bool m_wrrq;        // U19-13
+	bool m_rdrq;        // U19-7
+	bool m_uart_cmd;    // U10-15
+	bool m_uart_wr_mode;// U17-15
+	bool m_flg;         // U9-10
+	bool m_half_baud;   // U21-13
+	bool m_baud_div;    // U21-1
+	bool m_r4_dir;      // U19-4
+	bool m_loopback;
+	uint8_t m_r4in_data;    // U29, U30
+	uint8_t m_r4out_data;   // U26, U27
+	uint8_t m_lineout;  // U28
+
+	void int_reset();
+	void update_flg();
+	void update_irq();
+	void uart_rd();
+	void uart_wr();
+	void write_uart(bool cmd , uint8_t data);
+};
+
+// device type definitions
+DECLARE_DEVICE_TYPE(HP98036_IO_CARD, hp98036_io_card_device)
+
+#endif // MAME_BUS_HP9845_IO_98036_H
diff --git a/src/devices/bus/hp9845_io/hp9845_io.cpp b/src/devices/bus/hp9845_io/hp9845_io.cpp
index a6d09154671..bf304622f24 100644
--- a/src/devices/bus/hp9845_io/hp9845_io.cpp
+++ b/src/devices/bus/hp9845_io/hp9845_io.cpp
@@ -12,6 +12,7 @@
 #include "hp9845_io.h"
 #include "98032.h"
 #include "98035.h"
+#include "98036.h"
 #include "98034.h"
 #include "98046.h"
 
@@ -36,6 +37,7 @@ hp9845_io_slot_device::hp9845_io_slot_device(const machine_config &mconfig, cons
 	option_add("98032_gpio" , HP98032_IO_CARD);
 	option_add("98034_hpib" , HP98034_IO_CARD);
 	option_add("98035_rtc" , HP98035_IO_CARD);
+	option_add("98036" , HP98036_IO_CARD);
 	option_add("98046" , HP98046_IO_CARD);
 	set_default_option(nullptr);
 	set_fixed(false);