SA818PRO vs. SA818S: Upgrade & Selection Guide for Voice Intercom Modules

Introduction

In the wireless communication module space, the SA818 series is widely used in intercom applications thanks to its stability and strong value. This guide provides an in-depth comparison of two key models in the series: SA818S and its upgraded version SA818PRO. While both offer highly consistent core voice intercom functionality, they differ in key capabilities and target applications.

1. Product Positioning & Key Differences

SA818PRO is an upgraded version based on SA818S.

• SA818S: A stable, high-sensitivity voice-only intercom module. Its key strengths include an integrated LNA delivering -124 dBm receive sensitivity and fine control over audio filters. It focuses on high-quality, long-range voice communication and is better suited for traditional intercom applications where voice is the primary requirement.

• SA818PRO: A “voice + data” communication module. Building on SA818S’s voice capability, it adds three core features—data transmission, higher output power, and firmware upgrade support—making it suitable for IoT applications, smart control scenarios, and more complex intelligent-use requirements.

2. Core Feature Comparison: Three Key Advantages of the PRO Version

3. In-Depth RF Performance Comparison

3.1 Transmit Power

This is one of the most noticeable differences.

SA818PRO provides higher output power than SA818S. At 4.0V, SA818PRO typically outputs 1.6W; when the supply rises to 5.0V, it can reach a peak of 2.0W. Under the same conditions, this translates to stronger penetration and longer communication distance.

3.2 Receive Sensitivity

Both modules integrate an LNA (low-noise amplifier) and therefore achieve -124 dBm high receive sensitivity, maintaining stable links even in weak-signal environments.

3.3 Operating Frequency Bands

The band support is slightly different, but both cover mainstream VHF and UHF.

• SA818PRO

  • UHF: 400–480 MHz

  • VHF: 134–174 MHz

  • Note: choose either UHF or VHF; customizable options: 200–260 MHz, 470–520 MHz

• SA818S

  • UHF: 400–480 MHz

  • VHF: 134–174 MHz

  • Note: choose either UHF or VHF; customizable options: 200–260 MHz, 470–520 MHz

4. Hardware & Protocol Comparison

4.1 Hardware Interface & Compatibility

The two modules are highly compatible in both hardware and software interfaces. SA818PRO is largely pin- and protocol-compatible with SA818S. Except for the pin used for firmware upgrades, the remaining interfaces are the same—allowing users to upgrade based on an existing design without changing the PCB.

The only physical difference is Pin 2:

• SA818PRO: Pin 2 = UPDATA, used for firmware upgrade

• SA818S: Pin 2 = NC (not connected)

This design makes it easy to upgrade an existing SA818S design to SA818PRO and gain data transmission + firmware upgrade capabilities without PCB changes.

4.2 Communication Protocol (AT Commands)

• Shared commands: Most basic AT commands are the same (e.g., frequency setting, volume, squelch, etc.).

• SA818PRO-only commands: AT+TXOMES (send data) and +RXOMES (receive data).

• SA818S-only commands: AT+SETFILTER (set audio filters).

5. Online Firmware Upgrade Capability

Product extensibility is crucial for keeping up with fast-changing technical needs. SA818PRO supports online firmware upgrades via UART, enabling future feature iterations. Developers can fix potential issues or add new features without hardware changes, helping extend product lifetime and reduce maintenance complexity.

6. Manufacturing & Certifications

The SA818S module is manufactured using a lead-free process and complies with RoHS and REACH standards. A CE-certified version is available; in addition, a version designed to meet CE design requirements can be provided to satisfy market access needs across different regions. SA818Pro can also provide a CE-certified version to meet different market requirements.

7. Selection Recommendations

Technical Specifications Summary Table