VSH101 1-Lead ECG Holter Communication Packet Command
VSH101 BLE Communication Flow
After establishing a connection with VSH101, the initial communication flow is as follows:
If the VSC MODE has not been executed, instructions must be transmitted every 10 seconds to maintain the connection.
The VSC MODE START and VSC MODE STOP command are simple. Like the other BLE commands introduced before. The VSC MODE READ command will be a little more complicated. When user issues the VSC_MODE_READ command, device will send back 968 or 576 bytes data. The next section will give you a more detail description about the VSC Mode Data Format. Each VSC MODE READ command carries 200 ms ECG data and related information. It means user has to issues at lease 5 times VSC MODE READ command every second or the data will be overflow.
When the APP uses VSC MODE READ for real-time ECG data and related information, the communication transmission interval should be less than 200 milliseconds.
| Hour | Min | Sec | Delta Time | Delta Send | Event |
| 15 | 24 | 37.724 | [Cmd]Vsc Mode Read | ||
| 15 | 24 | 37.867 | 0.143 | BLE_VSC_MODE_READ ID = 1 | |
| 15 | 24 | 37.877 | 0.01 | 0.153 | [Cmd]Vsc Mode Read |
| 15 | 24 | 38.023 | 0.146 | BLE_VSC_MODE_READ ID = 2 | |
| 15 | 24 | 38.05 | 0.027 | 0.173 | [Cmd]Vsc Mode Read |
| 15 | 24 | 38.228 | 0.178 | BLE_VSC_MODE_READ ID = 3 | |
| 15 | 24 | 38.246 | 0.018 | 0.196 | [Cmd]Vsc Mode Read |
| 15 | 24 | 38.41 | 0.164 | BLE_VSC_MODE_READ ID = 4 | |
| 15 | 24 | 38.418 | 0.008 | 0.172 | [Cmd]Vsc Mode Read |
| 15 | 24 | 38.617 | 0.199 | BLE_VSC_MODE_READ ID = 5 |
VSH101 BLE Profile :
- Service profile: 6e400001-b5a3-f393-e0a9-e50e24dcca9e
- Write Characteristic profile: 6e400002-b5a3-f393-e0a9-e50e24dcca9e
- Notify Characteristic profile: 6e400003-b5a3-f393-e0a9-e50e24dcca9e
Write Characteristic Profile Packet Command Data Format :
PCode : The Write/Noitfy Characteristic command is same value, set same the ‘Cmd’ byte.
Group : The Group Command byte.
Cmd. : The Group sub Command byte.
ChkSum : The (Check Sum) is the sum of the entire packet.
MISO : Setting the notify receive length. (Little Endian)
MOSI : Setting the write command data length.(Little Endian)
Parameter Data : The parameter setting.(Little Endian)
Cmd Data : The data for command. (Little Endian)
Notify Characteristic Profile Packet Command Data Format :
PCode. : The write/notify command is same, usually same the “Cmd” byte.
Group : The group same the write command.
Ack : Confirm that the ‘Ack’ byte is ‘A’, then the command is correct this time and reply, otherwise will receive ‘N’.
ChkSum : (check sum) is the sum of bytes % 256 of the entire packet.
Index : The receive data memory index.(Little Endian)
Length : The packet data length.(Little Endian)
Cmd Data : The data for command.(Little Endian)
Check Sum Data Get Example Code:
VSH101 Packet Command Table
| Name | PCode | Group | Cmd | Description |
| Version | 0x00 | 0xC0 | 0x00 | Device FW Version |
| Time Set | 0x40 | 0xC0 | 0x40 | Set Device Time |
| Time Get | 0x41 | 0xC0 | 0x41 | Get Device Time |
| VSC Mode Start | 0x64 | 0xC2 | 0x64 | VSC MODE Measurement Start, VSC MODE Flow Chart |
| VSC Mode Stop | 0x65 | 0xC2 | 0x65 | VSC MODE Measurement Stop, VSC MODE Flow Chart |
| VSC Mode Read | 0x6A | 0xC2 | 0x6A | VSC MODE Read Data, VSC MODE Flow Chart |
| VSC Mode Type Set | 0x70 | 0xC2 | 0x70 | VSC MODE TYPE Setting |
| Soft Register Read | 0x00 | 0xA5 | 0x00 | Soft Register Command Read |
| Soft Register Write | 0x01 | 0xA5 | 0x01 | Soft Register Command Write |
| File List Clear | 0x70 | 0xAC | 0x70 | Clear Data Flash List |
| File List Read | 0x71 | 0xAC | 0x71 | read the Data Flash File List Data |
| VSC File Mode Start | 0x71 | 0xC2 | 0x71 | VSC File mode start command |
| VSC File Mode Stop | 0x72 | 0xC2 | 0x72 | VSC File mode stop command |
| VSC File Mode Read | 0x73 | 0xC2 | 0x73 | VSC File mode Read Command ( read back same VSC Mode Read) |
| VSC File Status Info | 0x74 | 0xC2 | 0x74 | Read VSC File status Info. |
| VSC File Mode Read Ex | 0x76 | 0xC2 | 0x76 | VSC File mode Read Command Ex |
1. Version Packet Command
Name | Hex Data |
PCode | 0x00 |
Group Id | 0xC0 |
Cmd | 0x00 |
Check sum | 0xE0 |
MOSI | 0x0000 |
MISO | 0x0020 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
2. Time Get Packet Command
Name | Hex Data |
PCode | 0x41 |
Group Id | 0xC0 |
Cmd | 0x41 |
Check sum | 0x52 |
MOSI | 0x0000 |
MISO | 0x0010 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
3. Time Set Packet Command
Name | Hex Data |
PCode | 40 |
Group Id | C0 |
Cmd | 40 |
Check sum | 44 |
MOSI | 0x0010 |
MISO | 0x0000 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data | E7 07 05 11 13 13 17 08 3B D8 64 64 80 70 00 00 |
4. VSC Mode Type Set Packet Command
Name | Hex Data |
PCode | 0x70 |
Group Id | 0xC2 |
Cmd | 0x70 |
Check sum | 0xAB |
MOSI | 0x0004 |
MISO | 0x0000 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data | 01 00 00 00 |
5. VSC Mode Start Packet Command
Name | Hex Data |
PCode | 0x64 |
Group Id | 0xC2 |
Cmd | 0x64 |
Check sum | 0x8A |
MOSI | 0x0000 |
MISO | 0x0000 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
6. VSC Mode Stop Packet Command
Name | Hex Data |
PCode | 0x65 |
Group Id | 0xC2 |
Cmd | 0x65 |
Check sum | 0x8C |
MOSI | 0x0000 |
MISO | 0x0000 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
7. VSC Mode Read Packet Command
Name | Hex Data |
PCode | 0x6A |
Group Id | 0xC2 |
Cmd | 0x6A |
Check sum | 0xE3 |
MOSI | 0x0000 |
MISO | 0x0238 |
Parameter Data | 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
Cmd Data format “index” set loops back from 0 to 999 after VSC Mode starts executing.
When Packet “index” loops back from 0 to 999 after VSC Mode starts executing, if 8000 is received, the data is not ready or 8000 is received for more than 1 second in a row, the VSC MODE Queue is overflowed
VSC MODE TYPE 0 Data Format
As mentioned, There are 968 bytes of returning data of VSC MODE READ. It includes two parts:
ECG DATA (800 bytes) – 2 channel ECG datas
INFO DATA (168 bytes) – 42 information
The detail description is listed below:
The INFO Data included 30 information for user to do the monitoring. It is listed below:
Data Structure and Specifications
The data packet includes Time (1), Temperature (2), ECG data (3, 4), G-Sensor (5, 6, 7), Battery Status (8, 9), HRV (10–16), Barometer values (17, 18), ATR data (27, 28), and the VSC Mode start time (29). Additionally, it contains five G-Sensor data points captured during the period (GS_X0..4, GS_Y0..4, GS_Z0..4).
Data Conversion Note: Except for the G-Sensor data points, all values are converted and processed as 4-byte floats.
G-Sensor Monitoring
The internal G-Sensor continuously monitors patient activity at a sampling rate of 25 Hz. Each VSC Mode data block covers a 200 ms window, which consistently contains 5 G-Sensor points (GS_X0..4, GS_Y0..4, GS_Z0..4) to align with the sampling frequency.
ATR (Annotation Trigger Record)
The ATR is used to mark specific ECG-related or physiological events. The encoding follows the PhysioNet ECG code definitions (referenced from the PhysioNet Archive), with the following addition:
#define ATR_NONE (255)
ATR Timestamp Calculation: To ensure precise alignment between the ATR events and the continuous physiological data stream, the actual timestamp is calculated as follows:
ATR Timestamp = VSC_Mode_Start_UTC + (ATR_TIME / 1000)
VSC_Mode_Start_UTC: The reference timestamp from Field 29.
ATR_TIME: The offset value expressed in milliseconds.
VSC MODE TYPE 1 Data Format
As mentioned, There are 568 bytees of returning data of VSC MODE READ. It includes two parts:
ECG DATA (400 bytes) – 1 channel ECG datas
INFO DATA (168 bytes) – 42 information
The detail description is listed below:
The INFO Data included 30 information for user to do the monitoring. It is listed below:
Data Structure and Specifications
The data packet includes Time (1), Temperature (2), ECG data (3, 4), G-Sensor (5, 6, 7), Battery Status (8, 9), HRV (10–16), Barometer values (17, 18), ATR data (27, 28), and the VSC Mode start time (29). Additionally, it contains five G-Sensor data points captured during the period (GS_X0..4, GS_Y0..4, GS_Z0..4).
Data Conversion Note: Except for the G-Sensor data points, all values are converted and processed as 4-byte floats.
G-Sensor Monitoring
The internal G-Sensor continuously monitors patient activity at a sampling rate of 25 Hz. Each VSC Mode data block covers a 200 ms window, which consistently contains 5 G-Sensor points (GS_X0..4, GS_Y0..4, GS_Z0..4) to align with the sampling frequency.
ATR (Annotation Trigger Record)
The ATR is used to mark specific ECG-related or physiological events. The encoding follows the PhysioNet ECG code definitions (referenced from the PhysioNet Archive), with the following addition:
#define ATR_NONE (255)
ATR Timestamp Calculation: To ensure precise alignment between the ATR events and the continuous physiological data stream, the actual timestamp is calculated as follows:
ATR Timestamp = VSC_Mode_Start_UTC + (ATR_TIME / 1000)
VSC_Mode_Start_UTC: The reference timestamp from Field 29.
ATR_TIME: The offset value expressed in milliseconds.
Soft Register Send Packet Format
Soft Register Table
| SREG NAME | SREG TYPE | Value Byte Size | Note |
| SREG_DEVICE_NAME | STRING | 20 | BLE Device Name |
| SREG_DEVICE_RESET | 0 | SREG Write then reset device | |
| SREG_DEVICE_SSN | STRING | 32 | Device SSN |
| SREG_MEAS_LEAD_OFF | INT | 4 | 0: Disable, 1: Enable |
| SREG_DEVICE_ID | INT | 4 | Device ID |
| SREG_DEVICE_BEACON | INT | 4 | 0: Disable, 1: Enable |
| SREG_VSC_MODE_TYPE | INT | 4 | 0: Type 0, 1: Type 1 |
| SREG_CHARG_POWER_DOWN | INT | 4 | 0: Disable, 1: Enable |
| SREG_ADVERTISING_INTERVAL | INT | 4 | advertising interval setting range : 20 ~ 1000 (mSec) |
| SREG_ADVERTISING_FIXED | INT | 4 | 0: Disable, 1: Enable |
| SREG_FILE_RING_MODE | INT | 4 | 0: Disable, 1: Enable |
8. Soft Register Write Packet Command
9. Soft Register Read Packet Command
10. VSC File Start Packet Command
Name | Hex Data |
PCode | 0x71 |
Group Id | 0xC2 |
Cmd | 0x71 |
Check sum | 0xA8 |
MOSI | 0x0000 |
MISO | 0x0004 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
11. VSC File Stop Packet Command
Name | Hex Data |
PCode | 0x72 |
Group Id | 0xC2 |
Cmd | 0x72 |
Check sum | 0xA6 |
MOSI | 0x0000 |
MISO | 0x0000 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
12. VSC File Read Packet Command (VSC Type 1)
Name | Hex Data |
PCode | 0x73 |
Group Id | 0xC2 |
Cmd | 0x73 |
Check sum | 0xDA |
MOSI | 0x0008 |
MISO | 0x0238 |
Parameter Data | 67 52 D3 64 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
When the read packet index is 8000, resend after a delay of 100 ~ 200 milliseconds.
Each individual data is generated every 200 milliseconds.and the data from to the next second is as follows:
13. VSC File Status Infomation Packet Commnad
Name | Hex Data |
PCode | 0x74 |
Group Id | 0xC2 |
Cmd | 0x74 |
Check sum | 0xCA |
MOSI | 0x0000 |
MISO | 0x0020 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
14. File List Get Packet Command
Name | Hex Data |
PCode | 0x71 |
Group Id | 0xAC |
Cmd | 0x71 |
Check sum | 0xDA |
MOSI | 0x0000 |
MISO | 0x0144 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
Each item in the file consists of the following information, each occupying 16 bytes:
- Start UTC (Coordinated Universal Time at the beginning)
- End UTC (Coordinated Universal Time at the end)
- Start Page (Starting data flash page index)
- End Page (Ending data flash page index)
There can be a maximum of 20 items. Additionally, there is a count represented using 4 bytes, indicating the total 324 bytes.
15. File List Clear Packet Command
Name | Hex Data |
PCode | 0x70 |
Group Id | 0xC2 |
Cmd | 0x70 |
Check sum | 0x8C |
MOSI | 0x0000 |
MISO | 0x0000 |
Parameter Data | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
16. VSC File Read EX Command
Name | Hex Data |
PCode | 0x76 |
Group Id | 0xC2 |
Cmd | 0x76 |
Check sum | 0x8C |
MOSI | 0x0008 |
MISO | 0x0238 |
Parameter Data | 0F B5 C0 69 00 00 00 00 00 00 00 00 00 00 00 00 |
Cmd Data |
When the read packet index is 8000, resend after a delay of 100 ~ 200 milliseconds.
