Mitsubishi Electric A/C via Intesis ME-AC-MBS interface

Register map(s) for this device, each at the trust rung it earned. Addresses are 0-based as on the wire. Word order and scaling are confirmed at the hardware-verified rung and at no rung below it.

interop-verified

Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.

point	address (0-based)	type	scale	unit
ac_unit_on_off	0	U16	1
ac_unit_mode	1	U16	1
ac_unit_fan_speed	2	U16	1
ac_unit_vane_position	3	U16	1
ac_unit_temperature_setpoint	4	U16	1	°C
ac_unit_ambient_temperature	5	U16	1	°C
window_contact	6	U16	1
device_disablement	7	U16	1
ir_remote_command_disablement	8	U16	1
ac_unit_operation_time	9	U16	1	h
ac_unit_alarm_status	10	U16	1
error_code	11	U16	1
ac_model	12	U16	1
open_window_switch_off_timeout	13	U16	1	min
modbus_rtu_baud_rate	14	U16	1
device_modbus_slave_address	15	U16	1
software_version	50	U16	1

link settings as documented (unverified): RTU; default 9600 8N1; unit ID 0; FC 03,04,06,16; Although function 16 is allowed, the interface does not allow write operations on more than 1 register with the same request, this means that length field should always be 1 when using this function for writes.

bench facts as documented (unverified)

terminals	plug-in terminal block of 2 poles
A/B polarity	A B
termination	on-board terminator resistor of 120Ω selectable via DIP-switch P5
connector	plug-in terminal block
isolation	1000 VDC isolation voltage, 1000 MΩ isolation resistance
wiring notes	Direct connection to the AC indoor unit via CN92 (Mr.Slim) or CN105 (other models).
broadcast	supported
protocol notes	Write operations on more than 1 register with the same request are not allowed.
firmware register	50
power	External power not required.
environment	Operating Temperature: -40 ... 85ºC, Operating Humidity: <95% RH, non-condensing
doc revision	rev.8
firmware applicability	v.1.13

field reports — community-sourced, unverified (checked 2026-06-11)

confirmed: Baud rates [2400, 9600, 19200, 57600] with default 9600, 8N1 framing — confirmed by IntesisBox ME-AC-MBS-1 v.1.13 User Manual (rev.8)
confirmed: Function codes 3, 4, 6, 16 supported, but writes with function 16 are restricted to a length of 1 register — confirmed by IntesisBox ME-AC-MBS-1 v.1.13 User Manual (rev.8)
confirmed: Direct connection to the AC indoor unit via CN92 or CN105 — confirmed by IntesisBox ME-AC-MBS-1 v.1.13 User Manual (rev.8)
confirmed: Register map addresses (ac_unit_on_off @ 0, ac_unit_alarm_status @ 10, error_code @ 11, software_version @ 50) — confirmed by IntesisBox ME-AC-MBS-1 v.1.13 User Manual (rev.8)

The trust ladder

Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.

generated — A prompt produced it. Unproven — anyone can regenerate this.
structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
interop-verified — Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.
simulator-verified — Decoded correctly against a protocol emulator seeded with known-true values — catches word-order/scaling errors vs the emulator, not the physical device.
hardware-verified x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.

If your device isn't here, upload its register map. Generation is free, and the connector keeps the rung it earns under testing.

To prove a connector against your own device, order hardware verification. If it doesn't verify, you don't pay.

Platform builders can license the verified library: machine-readable maps, the firmware matrix, API access.