What is Master-Slave?

Master-Slave is a distributed system architecture pattern that achieves efficient collaboration and resource management through clear role division.

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Master node: Orchestrates core decision-making, responsible for data writing, task scheduling, and global coordination, holding system control (e.g., database master handling write operations, Bluetooth master initiating connections).

Slave node: Passively receives data or instructions synchronized from the master node, undertaking auxiliary functions such as sharing read loads, backing up data, and executing distributed tasks 。

This architecture is widely applied in databases (e.g., MySQL master-slave replication), communication protocols (e.g., Bluetooth, RS485), and distributed storage (e.g., HDFS). Its core advantages lie in enhancing system availability, scalability, and fault tolerance.

Bluetooth implements master-slave communication via Piconets, where one master connects up to 7 slaves using Time-Division Multiple Access (TDMA). The 2025 Bluetooth 5.4 protocol enhances master-slave efficiency with 255-byte broadcast payloads and channel sounding ranging, improving reliability in smart home and industrial IoT scenarios.

Bluetooth 5.4 Key Technical Parameters 

Parameter

Master Device

Slave Device

Connection Limit

Up to 7 slaves (piconet)

Connects to 1 master only

Power Consumption

Higher due to continuous scanning

<1μA with broadcast interval >100ms

Data Rate

Supports LE Audio (2Mbps)

Supports HDT high-throughput mode

Localization

±1m ranging via channel sounding

Responds to master localization requests

Bluetooth Master-Slave Typical Application Scenarios
1. Consumer Electronics: Audio & Wearables
  • Bluetooth Headsets: Operate as slaves receiving audio streams from phones/PCs (masters). 2025’s LE Audio enhancements enable seamless master-switching (e.g., transitioning calls between devices).

  • Health Monitors: Smart bracelets (slaves) sync heart rate/step data to phones (masters) every 5 minutes, achieving >30-day battery life via Bluetooth 5.4’s low-power modes.

2. Smart Home: Multi-Device Coordination
  • Smart Speakers: Act as masters to control lights/curtains via voice commands (e.g., sending "turn on lights" instructions to slave bulbs).

  • Environmental Sensors: Temperature/humidity sensors (slaves) broadcast data every 100ms; gateways (masters) aggregate and upload to the cloud, supporting up to 32 nodes.

3. Industrial IoT: Low-Latency Data Acquisition
  • Production Line Monitoring: PLC controllers (masters) poll工位 sensors (slaves) with <3ms latency via Bluetooth 5.4’s ultra-low-latency HID mode.

  • Asset Tracking: BLE beacons (slaves) broadcast location data; forklift terminals (masters) upload to management systems with ±0.5m accuracy.

4. Automotive Electronics: Digital Keys

Per the 2025 ICCE Bluetooth Specification (>97% adoption), phones (masters) connect to vehicle Bluetooth (slaves) via UUID 0x184B, enabling encrypted key exchange and keyless entry.

RS485 Hub  Master-Slave

E810-R21/E810-R41 is a multi RS-485 to 1 RS-485 cache type isolation repeater from EBYTE. The RS485 hub is a communication device that supports 2/4 RS-485 master devices and 1 RS-485 slave device. Optical isolation technology is used to protect the master and slave devices from interference. The circuit adopts EMC level 3 standard for design, with 1.5KV isolation voltage, electrostatic protection of contact discharge 4KV,air discharge 8KV, and differential mode 1KV and common mode 2KV lightning surge protection, which can effectively isolate the hazards caused by lightning and static electricity to the equipment. No need to configure, transparent data transmission between master and slave interfaces.

This product is suitable for automation control system, monitoring system, alarm, access control system, IC card charging, meter reading, one card, parking lot charging and other integrated RS485 communication system.