---
title: "IntesisBOX TO-RC-MBS-1"
description: "Control Toshiba VRF/Digital AC via Modbus — ON/OFF, mode, fan speed, vane, thermostat and error monitoring. TapHome template for IntesisBOX TO-RC-MBS-1."
url: "https://taphome.com/en/compatibility/intesisbox-to-rc-mbs-1/"
language: en
lastmod: 2026-10-08
generator: hugo
ai:
  topics: ["modbus-tcp","air-conditioning","hvac-gateway","toshiba-ac","modbus-rtu-to-tcp","eia-485"]
  questions: ["How to integrate Toshiba VRF/Digital air conditioning with TapHome?","What devices does the IntesisBOX TO-RC-MBS-1 TapHome template provide?","How to configure DIP switches on IntesisBOX TO-RC-MBS-1 for TapHome?","Why does the thermostat show incorrect temperature on IntesisBOX TO-RC-MBS-1?","How to connect IntesisBOX TO-RC-MBS-1 to TapHome via Modbus TCP?","What is the difference between x1 and x10 temperature format on the IntesisBOX?"]
---

# IntesisBOX TO-RC-MBS-1

Communication: Modbus TCP

- [HMS Networks Product Page](https://www.hms-networks.com/p/inmbstos001r000-toshiba-vrf-and-digital-systems-to-modbus-rtu-interface)
- [Intesis HVAC Compatibility Tool](https://compatibility.intesis.com/)

> Network address
> 
> TapHome reaches this device at the address entered on import. Give the device a fixed address — an IP reservation in the router, or its mDNS name if it supports one — otherwise the integration stops working when the router changes the address.
> 
> [Network Preparation](https://taphome.com/en/docs/setup/network-preparation/)

## Integration guide

The IntesisBOX TO-RC-MBS-1 (order code INMBSTOS001R000) is a Modbus gateway by Intesis (HMS Networks) that interfaces Toshiba VRF and Digital Inverter air conditioning indoor units with Modbus RTU (EIA-485) networks. TapHome connects to the gateway via Modbus TCP using a TCP-to-RTU bridge — the gateway itself communicates with the AC unit over the proprietary Toshiba AB bus.

The template provides ON/OFF control, operating mode selection, fan speed adjustment, vane position control, thermostat with setpoint and current temperature, and error code monitoring. Up to 16 indoor units can be connected to a single gateway but are controlled as one group (not individually).

## Wiring

The gateway has two connection ports:

- **AB bus connector** (2 poles) — connects to the Toshiba AC indoor unit's AB bus (no polarity, max 500 m / 1,640 ft)
- **EIA-485 connector** (2 poles, A+ B-) — connects to the Modbus RTU bus (polarity must be observed, max 1,200 m / 3,937 ft)

The gateway is powered directly from the AC indoor unit (14 VDC) — no external power supply is needed.

![IntesisBOX TO-RC-MBS-1 connection diagram — Toshiba AB bus and EIA-485 Modbus RTU](https://taphome.com/images/compatibility/intesisbox-to-rc-mbs-1/wiring-diagram_hu_46625ddc19854c99.jpg)

**Connection methods:**
- **With wired remote controller:** The gateway connects in parallel on the AB bus alongside the Toshiba remote controller
- **Without remote controller:** The gateway connects directly to the AC indoor unit AB bus terminals

> [!WARNING]
> If a wired remote controller of the AC manufacturer is connected on the same AB bus, communication may shut down. The gateway can coexist with a remote controller only when configured as bus slave (SW1 positions 1-2 set to ON, and the remote controller configured as Header).

### EIA-485 bus termination

A 120 ohm termination resistor is required at each end of the EIA-485 bus. The gateway has a built-in 120 ohm resistor controlled by DIP switch SW4-P4 (OFF = connected, ON = disconnected). Leave SW4-P4 at OFF only if the gateway is at the physical end of the bus. Loop or star topologies are not allowed — use daisy-chain only.

## DIP switch configuration

The gateway has three DIP switch banks: SW1 (AC unit features), SW3 (Modbus slave address and baud rate), and SW4 (temperature format, baud rate, termination). All DIP switch changes require a power cycle to take effect.

![IntesisBOX TO-RC-MBS-1 DIP switch locations — SW1, SW3, SW4](https://taphome.com/images/compatibility/intesisbox-to-rc-mbs-1/dip-switch-layout_hu_f6e8b3557df58695.jpg)

### AC indoor unit type (SW1-P1..P2)

Positions 1 and 2 select the AC indoor unit type. Leave both OFF for standard operation.

| SW1-P1 | SW1-P2 | Unit type |
|--------|--------|-----------|
| OFF | OFF | Not specified — communicates with all indoor units (Default, recommended) |
| OFF | ON | RAV — advanced features for RAV units |
| ON | OFF | VRF (SMMS) — advanced features for VRF units |
| ON | ON | VRF (SHRM) — advanced features for VRF units |

### Bus master/slave mode (SW1-P4)

Position 4 selects the bus mode. Position 3 is not used.

| SW1-P4 | Bus mode |
|--------|----------|
| OFF | Master of bus AB (Default) — no Toshiba Remote Controller required |
| ON | Slave of bus AB — Toshiba Controller must be present, configured as Header |

> [!NOTE]
> For most installations, leave all SW1 positions at OFF (factory default). Only change if you need advanced indoor unit features (RAV/VRF) or bus slave mode (when a Toshiba remote controller is also connected).

### Temperature scaling (SW4-P1) — important for TapHome

The TapHome template divides temperature register values by 100. The default DIP switch setting transmits temperature in degrees (x1), so a setpoint of 22 °C is sent as register value 22. The template then divides by 100, yielding 0.22 °C — which is incorrect.

**Set SW4-P1 to ON** (decicelsius / x10 mode) so that 22.0 °C is transmitted as register value 220. The template divides by 100, yielding 2.2 °C — still incorrect at x10.

> [!WARNING]
> The template uses a division factor of 100, but neither the x1 nor x10 DIP switch setting produces correct values with this divisor. **Verify the actual register values with the Modbus debug tool in TapHome** and adjust the DIP switch or template scaling as needed for your installation. The same inconsistency exists in the Panasonic variant (PA-RC2-MBS-1).

| SW4 | Position | Description |
|------|----------|-------------|
| P1 | OFF | Temperature in degrees, x1 (Default) |
| P1 | ON | Temperature in decidegrees, x10 |
| P2 | OFF | Temperature in Celsius (Default) |
| P2 | ON | Temperature in Fahrenheit |
| P4 | OFF | Internal 120 ohm termination resistor connected |
| P4 | ON | No termination (Default) |

### Modbus address (SW3-P1..P6)

Binary-encoded slave address, range 1–63 (address 0 is the Modbus broadcast address — change the factory setting 0, e.g. to 1, to match the template default). Set to match the Slave ID entered during template import in TapHome.

Each DIP switch position has a binary weight — sum the ON positions to get the address:

| SW3 Position | P1 | P2 | P3 | P4 | P5 | P6 |
|--------------|----|----|----|----|----|----|
| **Weight** | 1 | 2 | 4 | 8 | 16 | 32 |

Common addresses:

| Address | P1 | P2 | P3 | P4 | P5 | P6 |
|---------|----|----|----|----|----|----|
| 0 (default) | OFF | OFF | OFF | OFF | OFF | OFF |
| 1 | ON | OFF | OFF | OFF | OFF | OFF |
| 2 | OFF | ON | OFF | OFF | OFF | OFF |
| 3 | ON | ON | OFF | OFF | OFF | OFF |
| 4 | OFF | OFF | ON | OFF | OFF | OFF |
| 5 | ON | OFF | ON | OFF | OFF | OFF |
| 10 | OFF | ON | OFF | ON | OFF | OFF |
| 16 | OFF | OFF | OFF | OFF | ON | OFF |
| 32 | OFF | OFF | OFF | OFF | OFF | ON |
| 63 | ON | ON | ON | ON | ON | ON |

### Baud rate (SW3-P7..P8 + SW4-P3)

Default: 9600 bps.

| SW3-P7 | SW3-P8 | SW4-P3 | Baud rate |
|--------|--------|--------|-----------|
| OFF | OFF | OFF | 2400 bps |
| ON | OFF | OFF | 4800 bps |
| OFF | ON | OFF | 9600 bps (default) |
| ON | ON | OFF | 19200 bps |
| OFF | OFF | ON | 38400 bps |
| ON | OFF | ON | 57600 bps |
| OFF | ON | ON | 76800 bps |
| ON | ON | ON | 115200 bps |

## TapHome connection

Since the IntesisBOX communicates via Modbus RTU (EIA-485), a **Modbus TCP-to-RTU bridge** is required between TapHome Core and the EIA-485 bus. TapHome connects to the bridge over the local network using Modbus TCP.

When importing the template in TapHome, provide:

- **IP Address** — the TCP-to-RTU bridge's IP on the local network (default: 192.168.0.1)
- **Slave ID** — the gateway's Modbus address set via DIP switches (default: 1)

## Device capabilities

The template exposes 6 devices communicating over holding registers H:0 through H:11.

### ON/OFF

Simple switch to turn the AC unit on or off. Reads and writes register H:0 (Bool). Poll interval: 2.5 s.

### Mode

Operating mode selector with 5 standard modes documented by Intesis:

| Value | Mode |
|-------|------|
| 0 | Auto |
| 1 | Heat |
| 2 | Dry |
| 3 | Fan |
| 4 | Cool |

The template defines 10 positions (values 0-9). Values 5-9 are not documented in the user manual and may be available on specific Toshiba models — most installations will only use the first five.

Reads and writes register H:1 (Int16). Poll interval: 2.5 s.

### Fan Speed

Fan speed selector with documented speeds:

| Value | Speed |
|-------|-------|
| 0 | Auto |
| 1 | Low |
| 2 | Mid |
| 3 | High |

The template defines 10 positions (values 0-9), including Turbo (value 5). The number of available fan speeds depends on the connected AC model — register H:21 reports the maximum number of fan speeds supported. Values beyond the model's maximum will have no effect.

Reads and writes register H:2 (Int16). Poll interval: 2.5 s.

### Vane Position

Vertical vane (louver) position control:

| Value (template) | Position |
|-------------------|----------|
| 0 | Auto |
| 1 | Position 1 (Horizontal) |
| 2 | Position 2 (Horizontal) |
| 3 | Position 3 (Medium) |
| 4 | Position 4 (Vertical) |
| 5 | Swing |
| 6-8 | Additional positions |
| 9 | Swirl |

> [!NOTE]
> The user manual documents Swing as value 10, but the template maps it to value 5 to create a contiguous range for the multi-value switch. Swirl (value 9) is a rotational airflow pattern available on select Toshiba models. Available vane positions depend on the connected indoor unit.

Reads and writes register H:3 (Int16). Poll interval: 2.5 s.

### Thermostat

Temperature setpoint (register H:4, read/write) and current reference temperature (register H:5, read-only). The template divides read values by 100 and multiplies written values by 100.

Temperature range: 16–32 °C (default setpoint range, model-dependent). The reference temperature shows the AC unit's own sensor reading — in Heat mode it reports ambient +0.5 °C, in Dry/Fan/Cool mode it reports ambient -0.5 °C. If an external temperature sensor value has been written to register H:22, register H:5 reports that value instead.

Poll interval: 2.5 s.

### Error Code

Read-only numeric value from register H:11. Key values:

| Value | Meaning |
|-------|---------|
| 0 | No error |
| 65535 (-1) | Communication error between gateway and AC unit |
| Other | Toshiba error code (see user manual Section 7 for 80+ error codes) |

Common error categories: C01-C31 (central controller), E01-E31 (addressing/communication), F01-F31 (sensor faults), H01-H31 (compressor), L01-L31 (incorrect settings), P01-P31 (indoor/outdoor unit).

Poll interval: 15 s.

### Additional capabilities

The gateway exposes several registers not included in the current TapHome template. Window Contact (H:6) provides energy-saving functionality by turning off the AC when a window opens. Interface and Remote Control Disablement registers (H:7, H:8) allow locking the gateway or the AC remote. Operation Time (H:9) tracks running hours, and Alarm Status (H:10) provides a binary alarm indicator.

For VRF and RAV systems, extensive advanced registers (H:4000+) report per-indoor-unit status including duty, defrost state, filter alarms, and detailed temperatures. Outdoor unit registers (H:4200+ for VRF-SMMSi/SHRM/SMMS, H:4400+ for RAV) expose pressures, discharge temperatures, compressor currents, and fan status. These can be added in a future template update.

## Troubleshooting

### No Modbus communication

1. Verify the AB bus is connected between the gateway and the AC indoor unit — the gateway requires AC unit power to operate
2. Check the green LED (L1): normal operation shows 100 ms ON / 1,900 ms OFF pattern; 500 ms ON / 500 ms OFF indicates a communication error
3. Confirm the slave address in TapHome matches the DIP switch setting on the gateway (SW3)
4. Ensure the TCP-to-RTU bridge is on the same network as TapHome Core
5. Verify the baud rate on the gateway matches the TCP-to-RTU bridge configuration (default: 9600 bps, 8N2)

### Error code 65535 continuously

This indicates the gateway cannot communicate with the Toshiba AC indoor unit over the AB bus. Check the AB bus wiring and verify the AC unit is powered on. If using a wired remote controller, ensure the SW1 bus master/slave configuration is correct.

### Temperature values are incorrect

The template uses a division factor of 100 for temperature registers. Verify the DIP switch SW4-P1 and SW4-P2 settings match the expected scaling. Use the Modbus debug tool in TapHome to read raw register values and compare with the actual temperature.

### Write operations not taking effect

The gateway supports Modbus function 16 (Write Multiple Registers) with a limitation: only 1 register can be written per request (length field must be 1). TapHome handles this correctly via the MODBUSWNE function in the template scripts. If issues persist, confirm the gateway firmware version — some features require firmware 2.3 or later.

## Available devices 6

These devices appear in TapHome after import.

IntesisBOX TO-RC-MBS-1 Module

ON/OFF Switch Read and write

Register: H:0 Bool

Values / States: ON · OFF

Read switch state

```taphome
MODBUSR(H, 0, Bool)
```

Write switch state

```taphome
MODBUSWNE(H, 0, Bool, St)
```

Mode Multi-value Switch Read and write

Operating mode — Auto, Heat, Dry, Fan, Cool (register H:1, values 0–4; positions 5–9 model-specific)

Register: H:1 Int16 numeric

Values / States: Auto · Heat · Dry · Fan · Cool

Read switch state

```taphome
MODBUSR(H, 1, Int16)
```

Write switch state

```taphome
MODBUSWNE(H, 1, Int16, Mu)
```

Fan Speed Multi-value Switch Read and write

Fan speed — Auto (0), Low (1), Mid (3), High (4), Turbo (5) (register H:2; additional positions model-dependent)

Register: H:2 Int16 numeric

Values / States: Auto · Low · Mid · High

Read switch state

```taphome
MODBUSR(H, 2, Int16)
```

Write switch state

```taphome
MODBUSWNE(H, 2, Int16, Mu)
```

Vane Position Multi-value Switch Read and write

Vertical vane position — Auto, 5 fixed positions, Swing, Swirl (register H:3; Swing remapped to value 5)

Register: H:3 Int16 numeric

Values / States: Position-1 (Horizontal) · Position-2 (Horizontal) · Position-3 (Medium) · Position-4 (Vertical) · Swing ON · Position-7 · Position-6 · Poistion-5 (Vetical)

Read switch state

```taphome
MODBUSR(H, 3, Int16)
```

Write switch state

```taphome
MODBUSWNE(H, 3, Int16, Mu)
```

Thermostat Thermostat Read and write

Temperature setpoint (H:4) and current reference (H:5) — raw values divided by 100; DIP switch config required

Register: H:4 Int16 Unit: °C numeric

Read temperature

```taphome
MODBUSR(H, 5, Int16) / 100
```

Read desired temperature

```taphome
MODBUSR(H, 4, Int16) / 100
```

Write desired temperature

```taphome
MODBUSWNE(H, 4, Int16, Se * 100)
```

Error Code Variable Read-only

Numeric error code from register H:11 — 0: no error, 65535: communication error, other: Toshiba fault code

Register: H:11 Int16 numeric

Read

```taphome
MODBUSR(H, 11, Int16)
```

**Connection:** Modbus TCP • Slave ID: $\[SlaveId]

Possible improvements (10)

- H:6 Window Contact — R/W, 0: Closed / 1: Open — energy saving feature, turns off AC when window opens
- H:7 Interface Disablement — R/W, 0: Enabled / 1: Disabled — disables INMBSTOS001R000 interface (non-volatile)
- H:8 Remote Control Disablement — R/W, 0: Enabled / 1: Disabled — disables AC remote control (non-volatile)
- H:9 Operation Time — R/W, 0–65535 hours — running hours counter (non-volatile)
- H:10 Alarm Status — R, 0: No alarm / 1: Alarm — binary alarm indicator
- H:22 External Sensor Ambient Temperature — R/W — overrides indoor unit's built-in temperature sensor; write 0x8000 to disable
- H:23 AC Setpoint Temperature (feedback) — R — current setpoint as reported by the indoor unit
- H:4000+ Advanced Indoor Unit Registers — R — per-unit status: exist, address, duty, defrost, filter alarm, thermos, room temp, suction temp, fan coil temps (requires SW1 indoor unit type config)
- H:4200+ Advanced Outdoor Unit Registers (VRF-SMMSi) — R — duty, pressures, discharge temps, suction temp, fan coil temps, currents, compressor revolutions, fan mode, IPDU temps (VRF systems only)
- H:4400+ Advanced Outdoor Unit Registers (RAV) — R — duty, evaporator temp, outdoor temp, discharge temp, suction temp, thyristor temp, compressor current/revolutions/hours, fan revolutions (RAV systems only)

## Import parameters

Enter these values when you import the XML.

| Asked in the app | Default       |
|------------------|---------------|
| Slave ID         | `1`           |
| IP address       | `192.168.0.1` |

## Sources

- IntesisBOX TO-RC-MBS-1 User Manual v2.9
  
  [www.hms-networks.com](https://www.hms-networks.com/docs/default-source/products/intesis/manuals-and-guides---manuals/user-manual-inmbstos001r000.pdf) 2026-03-31
  
  [PDF](https://taphome.com/compatibility/devices/intesisbox-to-rc-mbs-1/manufacturer/user-manual.pdf)
- HMS Networks Product Page — INMBSTOS001R000
  
  [www.hms-networks.com](https://www.hms-networks.com/p/inmbstos001r000-toshiba-vrf-and-digital-systems-to-modbus-rtu-interface) 2026-03-31

Manufacturer documents are © their respective owners. They are provided as published by the manufacturer, for reference only.

## Related Documentation

- [Modbus Integration](https://taphome.com/en/compatibility/modbus-guide/)
- [Modbus](https://taphome.com/en/docs/integration/modbus/)
- [Simple configuration using templates](https://taphome.com/en/docs/integration/modbus/templates/)
- [Modbus scripts and prefetch](https://taphome.com/en/docs/script/modbus-scripts/)
- [Modbus functions](https://taphome.com/en/docs/script/modbus/)
- [Modbus data types](https://taphome.com/en/docs/script/modbus-data-types/)