Mitsubishi CN105 Climate

The mitsubishi_cn105 component allows communication with Mitsubishi Electric indoor units using the CN105 connector.

The component communicates with the unit over UART and provides control and state reporting.

Hardware Connection

The CN105 connector exposes power and UART communication lines.

CN105 pinout

Pin	Function	Wire color	Device
1	NC
2	GND	orange	GND
3	5V	brown	5V
4	TX	blue	RX
5	RX	red	TX

CN105 connector wired to a D1 Mini Pro

WARNING

Verify the pinout and voltage levels before connecting.

This component requires a UART bus configured with:

• 8 data bits
• EVEN parity
• 1 stop bit
• Baud rate 2400 or 9600

NOTE

The required baud rate depends on the indoor unit. During initial setup, try both supported values if communication does not work.

Example configuration

uart:
  id: ac_uart
  tx_pin: GPIO1
  rx_pin: GPIO3
  data_bits: 8
  baud_rate: 2400
  parity: EVEN
  stop_bits: 1

climate:
  - platform: mitsubishi_cn105
    name: "Living Room AC"
    uart_id: ac_uart
    update_interval: 1s
    current_temperature_min_interval: 60s

WARNING

If you are using the Logger Component, make sure you are not using the same pins, or disable UART logging with:

logger:
  baud_rate: 0

Supported features

• Target temperature range: 16 °C to 31 °C
• Current temperature reporting
• Modes: OFF, AUTO, HEAT, COOL, DRY, FAN_ONLY
• Fan modes: AUTO, QUIET, LOW, MEDIUM, MIDDLE, HIGH

NOTE

Fan modes map to the following Mitsubishi fan speeds:

• AUTO → AUTO
• QUIET → QUIET
• LOW → SPEED 1
• MEDIUM → SPEED 2
• MIDDLE → SPEED 3
• HIGH → SPEED 4

Configuration variables

• uart_id (Optional, ID): The UART bus to use.

• update_interval (Optional, Time): Interval between status updates. Defaults to 1s. Lower values provide faster detection of external changes, for example when using the remote control.

• current_temperature_min_interval (Optional, Time): Minimum time between consecutive room temperature reads.

  This allows keeping a low update_interval (to quickly reflect changes, e.g. when using an IR remote) while avoiding excessive current temperature updates.

  Room temperature is still requested during regular polling cycles, so the effective update frequency is bounded by update_interval.

  Set to never to disable room temperature polling.

  Defaults to 60s.

• All other options from Climate.

Lambda calls

The following methods can be used from lambdas for advanced integrations:

• set_remote_temperature(float temperature)

  • Sends an external (remote) room temperature to the indoor unit.
  • Overrides the unit’s internal temperature sensor.
  • Values outside the supported range (8.0–39.5 °C) or NaN are ignored.

• clear_remote_temperature()

  • Clears the externally provided temperature.
  • Restores use of the unit’s internal temperature sensor.

NOTE

This does not modify the temperature reported by the A/C unit in its status/room temperature packets. The reported current temperature remains the value provided by the unit itself. Some units may reflect the externally provided temperature, while others may continue to report their internal sensor value.

Some units may automatically fall back to the internal sensor if no external temperature is sent.

In such cases, the external temperature should be sent periodically (e.g. using an interval).

Alternatively, clear_remote_temperature() can be called if the external sensor becomes unavailable for an extended period.

It is the user’s responsibility to tailor the update strategy and usage to their specific A/C unit and setup.

This is an advanced feature; users are expected to understand the implications of overriding the internal sensor. Depending on the unit, it may be necessary to explicitly call clear_remote_temperature() to restore normal operation. Improper use may lead to unexpected behavior.

Example:

climate:
  - platform: mitsubishi_cn105
    id: ac
    # ...

sensor:
  - platform: homeassistant
    id: living_room_temp
    entity_id: sensor.living_room_temperature
    on_value:
      then:
        - lambda: |-
            id(ac).set_remote_temperature(x);

See Also

• Climate Component