diff --git a/src/mame/wyse/wy50.cpp b/src/mame/wyse/wy50.cpp
index 36be3402e0b..93e636f33bf 100644
--- a/src/mame/wyse/wy50.cpp
+++ b/src/mame/wyse/wy50.cpp
@@ -53,6 +53,7 @@ public:
 		, m_pvtc(*this, "pvtc")
 		, m_sio(*this, "sio")
 		, m_beep(*this, "beep")
+		, m_aux(*this, "aux")
 		, m_chargen(*this, "chargen")
 		, m_videoram(*this, "videoram%u", 0U)
 	{
@@ -78,6 +79,7 @@ private:
 	void earom_w(u8 data);
 	u8 p1_r();
 	void p1_w(u8 data);
+	u8 p3_r();
 
 	void prg_map(address_map &map);
 	void io_map(address_map &map);
@@ -89,6 +91,7 @@ private:
 	required_device<scn2672_device> m_pvtc;
 	required_device<scn2661b_device> m_sio;
 	required_device<beep_device> m_beep;
+	required_device<rs232_port_device> m_aux;
 
 	required_region_ptr<u8> m_chargen;
 	required_shared_ptr_array<u8, 2> m_videoram;
@@ -239,20 +242,22 @@ void wy50_state::earom_w(u8 data)
 
 u8 wy50_state::p1_r()
 {
-	// P1.0 = AUX RDY
+	// P1.0 = AUX RDY (DTR)
 	// P1.1 = NVD OUT
 	// P1.4 = KEY (inverted, active high)
-	return 0xed | (m_earom->data_r() << 1) | (m_keyboard->sense_r() ? 0x00 : 0x10);
+	return 0xe4 | m_aux->dsr_r() | (m_earom->data_r() << 1) | (m_aux->cts_r() << 2) | (m_keyboard->sense_r() ? 0x00 : 0x10);
 }
 
 void wy50_state::p1_w(u8 data)
 {
 	// P1.2 = EXFONT
-	// P1.3 = AUX RTS
+	// P1.3 = AUX RTS (DSR)
 	// P1.5 = BEEPER
 	// P1.6 = REV/DIM PROT
 	// P1.7 (inverted) = 80/132
 
+	m_aux->write_dtr(BIT(data, 3));
+
 	m_beep->set_state(BIT(data, 5));
 
 	m_rev_prot = BIT(data, 6);
@@ -265,6 +270,11 @@ void wy50_state::p1_w(u8 data)
 	}
 }
 
+u8 wy50_state::p3_r()
+{
+	return m_aux->rxd_r() | 0xfe;
+}
+
 void wy50_state::prg_map(address_map &map)
 {
 	map(0x0000, 0x1fff).rom().region("maincpu", 0);
@@ -298,6 +308,8 @@ void wy50_state::wy50(machine_config &config)
 	m_maincpu->set_addrmap(AS_IO, &wy50_state::io_map);
 	m_maincpu->port_in_cb<1>().set(FUNC(wy50_state::p1_r));
 	m_maincpu->port_out_cb<1>().set(FUNC(wy50_state::p1_w));
+	m_maincpu->port_in_cb<3>().set(FUNC(wy50_state::p3_r));
+	m_maincpu->port_out_cb<3>().set(m_aux, FUNC(rs232_port_device::write_txd)).bit(1);
 
 	WY50_KEYBOARD(config, m_keyboard);
 
@@ -330,6 +342,8 @@ void wy50_state::wy50(machine_config &config)
 	modem.cts_handler().set(m_sio, FUNC(scn2661b_device::cts_w));
 	modem.dcd_handler().set(m_sio, FUNC(scn2661b_device::dcd_w));
 
+	RS232_PORT(config, m_aux, default_rs232_devices, "loopback");
+
 	SPEAKER(config, "speaker").front_center();
 	// Star Micronics QMB06 PZT Buzzer (2048Hz peak) + LC filter, output frequency is approximated here
 	BEEP(config, m_beep, 1000).add_route(ALL_OUTPUTS, "speaker", 0.10);
diff --git a/src/mame/wyse/wy60.cpp b/src/mame/wyse/wy60.cpp
index ee1d5dd298a..0e032490ef0 100644
--- a/src/mame/wyse/wy60.cpp
+++ b/src/mame/wyse/wy60.cpp
@@ -29,6 +29,7 @@ public:
 		, m_keyboard(*this, "keyboard")
 		, m_pvtc(*this, "pvtc")
 		, m_sio(*this, "sio")
+		, m_aux(*this, "aux")
 		, m_charram(*this, "charram")
 		, m_attrram(*this, "attrram")
 		, m_fontram(*this, "fontram", 0x2000, ENDIANNESS_LITTLE)
@@ -59,6 +60,7 @@ private:
 
 	void p1_w(u8 data);
 	u8 p1_r();
+	u8 p3_r();
 	void ea_w(int state);
 
 	void prog_map(address_map &map);
@@ -69,6 +71,7 @@ private:
 	required_device<wyse_keyboard_port_device> m_keyboard;
 	required_device<scn2672_device> m_pvtc;
 	required_device<scn2661b_device> m_sio;
+	required_device<rs232_port_device> m_aux;
 	required_shared_ptr<u8> m_charram;
 	required_shared_ptr<u8> m_attrram;
 	memory_share_creator<u8> m_fontram;
@@ -186,6 +189,7 @@ void wy60_state::sio_w(offs_t offset, u8 data)
 
 void wy60_state::p1_w(u8 data)
 {
+	// P1.0 -> _80/132
 	if (BIT(data, 0) != m_is_132)
 	{
 		m_is_132 = BIT(data, 0);
@@ -193,19 +197,30 @@ void wy60_state::p1_w(u8 data)
 		m_pvtc->set_unscaled_clock(m_is_132 ? 39.71_MHz_XTAL / 9 : 26.58_MHz_XTAL / 10);
 	}
 
+	// P1.1 -> EEPROM SDA
+	// P1.2 -> EEPROM SCL
 	// N.B. The current i2cmem emulation is a bit sensitive to the order of these writes.
 	m_eeprom->write_scl(BIT(data, 2));
 	m_eeprom->write_sda(BIT(data, 1));
 
-	m_keyboard->cmd_w(!BIT(data, 5));
+	// P1.3 -> AUX DSR
+	m_aux->write_dtr(BIT(data, 3));
 
-	// TODO: P1.3 -> AUX DSR
+	// P1.5 -> KBD CMD (transmitted through 74LS368)
+	m_keyboard->cmd_w(!BIT(data, 5));
 }
 
 u8 wy60_state::p1_r()
 {
-	// TODO: P1.4 <- AUX DTR
-	return (m_eeprom->read_sda() << 1) | (m_keyboard->data_r() ? 0 : 0x40) | 0xad;
+	// P1.1 <- EEPROM SDA
+	// P1.4 <- AUX DTR
+	// P1.6 <- KBD DATA (received through 74LS368)
+	return (m_eeprom->read_sda() << 1) | (m_aux->dsr_r() << 4) | (m_keyboard->data_r() ? 0 : 0x40) | 0xad;
+}
+
+u8 wy60_state::p3_r()
+{
+	return m_aux->rxd_r() | 0xfe;
 }
 
 void wy60_state::ea_w(int state)
@@ -250,7 +265,9 @@ void wy60_state::wy60(machine_config &config)
 	maincpu.set_addrmap(AS_IO, &wy60_state::ext_map);
 	maincpu.port_out_cb<1>().set(FUNC(wy60_state::p1_w));
 	maincpu.port_in_cb<1>().set(FUNC(wy60_state::p1_r));
-	maincpu.port_out_cb<3>().set(FUNC(wy60_state::ea_w)).bit(5);
+	maincpu.port_out_cb<3>().set(m_aux, FUNC(rs232_port_device::write_txd)).bit(1);
+	maincpu.port_out_cb<3>().append(FUNC(wy60_state::ea_w)).bit(5);
+	maincpu.port_in_cb<3>().set(FUNC(wy60_state::p3_r));
 
 	I2C_X2404P(config, m_eeprom);
 
@@ -284,7 +301,7 @@ void wy60_state::wy60(machine_config &config)
 	modem.cts_handler().set(m_sio, FUNC(scn2661b_device::cts_w));
 	modem.dcd_handler().set(m_sio, FUNC(scn2661b_device::dcd_w));
 
-	// TODO: AUX port connected to 8051
+	RS232_PORT(config, m_aux, default_rs232_devices, "loopback");
 }
 
 // CPU:   8051(202008-03)