What is a Bit Error Rate Test (BER/BERT)?

When digital communication links are pushed to ever higher speeds, reliability becomes critical. Even a small number of transmission errors can disrupt systems, reduce performance, or lead to costly downtime. To measure and validate that reliability, engineers use a Bit Error Rate Test (BER test).

What is BER / BERT?

The Bit Error Rate (BER) is the ratio between the number of received bits that contain errors and the total number of transmitted bits. In simple terms: it tells you how “clean” or “error-free” a digital communication channel is.

A Bit Error Rate Tester (BERT) is a specialised piece of equipment designed to generate test patterns, transmit them over the link under test, and compare the received data against the original. From this, it calculates the BER.

BERTs are especially important when working with high-speed digital interfaces such as:

• QPI (QuickPath Interconnect)
  
• FB-DIMM
  
• PCI Express®
  
• SATA / SAS
  
• USB
  
• Thunderbolt
  

These interfaces are at the heart of modern computing, storage, and communication systems. Ensuring they meet required BER levels is a key step in design verification, R&D, and compliance testing.

BER Testing in Telecom and Field Applications

While BERTs are widely used in laboratories and design environments, telecom and networking teams also rely on BER testing to validate live communication links. In this context, BER is used to confirm the performance of fibre optic, Ethernet, and transport networks.

Here, BER testing is often integrated into Ethernet, Fibre Channel, and transport testers. These portable instruments are designed for field deployment, enabling technicians to assess the quality of transmission channels in real-world conditions.

Typical field applications include:

• Telecom network commissioning and maintenance
  
• Fibre channel validation
  
• Ethernet throughput and quality testing
  
• Long-haul and metro transport network verification
  

VIAVI and EXFO: Leaders in BER Test Solutions

Two major players in this field are VIAVI and EXFO, both offering advanced BERT and network test platforms:

• VIAVI Solutions – Known for high-performance BERT instruments designed for lab validation and high-speed protocol testing. Their portfolio includes solutions for 400G/800G Ethernet and beyond.
  
• EXFO – Offers a wide range of test solutions, including BER functionality within their Power Blazer series and other modules, bridging the gap between lab testing and real-world telecom applications.
  

By combining dedicated BERTs for design verification with field-capable testers from VIAVI and EXFO, engineers and operators can cover the entire lifecycle: from R&D and prototyping to deployment and maintenance.

Why Rent a BERT or BER-Capable Tester?

Owning high-end BERT systems can represent a major investment. Renting offers several advantages:

• Flexibility: Access exactly the right tester for your project or deployment phase.
  
• Cost-efficiency: Avoid high upfront purchase costs while still getting access to the latest models.
  
• Scalability: Quickly ramp up your test capacity for large projects or temporary requirements.
  
• Trusted brands: RentalTec provides access to solutions from VIAVI, EXFO, and other leading vendors.
  

Whether you need a lab-grade BERT for high-speed protocol validation, or a field-ready Ethernet/Fibre/transport tester for telecom networks, RentalTec can provide the right equipment with expert support.

✅ Looking for a Bit Error Rate Test solution?
Explore our BER/BERT test set archive or our Ethernet, Fibre Channel & Transport testers, or contact our team for tailored advice.