(0x7B) Extended Connect Response
A response to an extended connect request, as sent in a (0x5B) Extended Connect Request packet. Appears to be used to identify information about the unit that the thermostat is connected to.
| Byte | Purpose | Possible Values | Supported by mUART | Notes |
|---|---|---|---|---|
| 0 | CommandType | 0xC9 | ||
| 1-6 | TBD | 0x03 | ||
| 7-15 | Unit Capabilities | (See below) |
| Byte | Bitmask | Purpose | Notes |
|---|---|---|---|
| 7 | 0x01 | ??? | Observed true |
| 7 | 0x02 | Heat Disabled (if true) | |
| 7 | 0x04 | ??? | Observed true |
| 7 | 0x08 | ??? | |
| 7 | 0x10 | Fan Bit A | |
| 7 | 0x20 | Vertical Vane support | |
| 7 | 0x40 | Vane swing support | Seems to cover both vane types, if horizontal vane exists. |
| 7 | 0x80 | ??? | |
| 8 | 0x01 | Dry function disabled (if true) | |
| 8 | 0x02 | Fan function disabled (if true) | |
| 8 | 0x04 | Has extended temperature range | Seems to determine if the A-scale is usable. |
| 8 | 0x08 | Fan Bit B | |
| 8 | 0x10 | Automatic Fan Speed disabled (if true) | |
| 8 | 0x20 | Installer Settings (Function) support | |
| 8 | 0x40 | Test Mode support | |
| 8 | 0x80 | Supports dry temperature | |
| 9 | 0x01 | Has status display | |
| 9 | 0x02 | Fan Bit C | |
| 9 | 0x04 | ??? | Observed true and false |
| 9 | 0x08 | ??? | |
| 9 | 0x10 | ??? | Observed true and false |
| 9 | 0x20 | ??? | Observed true and false |
| 9 | 0x40 | ??? | |
| 9 | 0x80 | ??? | Observed true and false |
| 10 | All | Minimum cool/dry temp setpoint | |
| 11 | All | Maximum cool/dry temp setpoint | |
| 12 | All | Minimum heating temp setpoint | |
| 13 | All | Maximum heating temp setpoint | |
| 14 | All | Minimum auto temp setpoint | |
| 15 | All | Maximum auto temp setpoint |
Bytes 10-15 appear to only be sent if the extended temperature range is supported by the unit.
Sample Packets:
[FC.7B.01.30.10] C9.03.00.20.00.0A.07.05.E4.25.A6.BC.94.B8.A6.B8 2D // SVZ-KP30NA
[FC.7B.01.30.10] C9.03.00.20.00.14.07.75.0C.05.A0.BE.94.BE.A0.BE A9 // MSZ-GL06NA
[FC.7B.01.30.10] C9.03.00.09.04.14.07.75.00.00.00.00.00.00.00.00 DB // MSZ-GE35VA
The number of allowed fan speeds is determined by fan bits A, B, and C, as calculated below:
def get_fan_speeds(capabilities: list[int]):
fan_speed_lut = { 1: 1, 2: 2, 0: 3, 4: 4, 6: 5 }
raw_speed = ((capabilities[0] & 0x10) >> 2) + \
((capabilities[1] & 0x08) >> 2) + \
((capabilities[2] & 0x02) >> 1)
return fan_speed_lut[raw_speed]The exact mapping as to fan speed names is currently unclear, though the below mapping seems reasonable:
{
1: ["ON"],
2: ["LOW", "HIGH"],
3: ["LOW", "MEDIUM", "HIGH"],
4: ["LOW", "MEDIUM", "HIGH", "VERY_HIGH"]
5: ["VERY_LOW", "LOW", "MEDIUM", "HIGH", "VERY_HIGH"]
}Note that these values may not correspond with the actual numbers provided to the fan system - verification will need to be done.
Known fan speed values (and model numbers associated with certain fan speed values) are below:
| Fan Speed Value | Model Numbers | Supported Modes |
|---|---|---|
| 3 | SVZ-KP30NA | 0x02 (Low) 0x03 (Medium) 0x05 (High) |
| 5 | MSZ-GS12NA | 0x01 (Quiet) 0x02 (Low) 0x03 (Medium) 0x05 (High) 0x06 (Very High) |
