Hi there！
I'd be happy to share with you about BER.
What is BER
The BER is a measure of the accuracy of data transmission within a specified period of time.
Bit error rate = Bit errors in transmission/Total number of transmitted codes x 100%.
If there are bit errors, there is a bit error rate. In addition, the BER is defined as the frequency at which bit errors occur. The IEEE802.3 standard defines a maximum acceptable BER of 
for 1000Base-T networks. This bit error rate standard is set for Pulse Amplitude Modulation (PAM-5) coding, which is also known as Gigabit Ethernet coding.
Conversion between the BER and the PLR (packet loss rate)
In the transmission field, the bit error rate (BER) and the packet loss rate (PLR) are two parameters frequently mentioned. How to convert the two parameters? A simple method for calculating the BER based on the PLR is as follows:
If the packet length is 1500 bytes, the PLR can reach 10E-4 only when the BER=(10E-4)×(1/1500/8)=8.33×10E-9 and BER reach 8.33 x 10E-9.
If the packet length is 64 bytes, BER=(10E-4)×(1/64/8)=2×10E-7
A more appropriate conversion method is:
The following figure shows the relationship between PLR and BER for different packet lengths (without considering error correction).
Mapping between BER and Q values
How to test the BER
Use a meter, such as an SDH tester and an E1 tester.
Pass the software test, such as the U2000 network management software.
Thank you!
