ZyXEL Communications PLA-407 User Manual

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 Chapter 6 The OS X Configuration Utility
PLA-407 User’s Guide
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Avg. Source PB CRC 
Error Rate
This field displays the average CRC (Cyclic Redundancy Check) 
error rate of transmission from the source device (as shown in 
the screen) received by destination Powerline device. 
 A Cyclic Redundancy Check (CRC) is used as a checksum to 
detect alteration of data during transmission. The CRC error 
check is performed after Forward Error Correction. If the error 
rate after FEC error correction is still high, then this indicates a 
lot of noise at all frequencies on this section of your Powerline 
network. Data transmission rates are reduced if there is a lot of 
noise on the line.
Avg. Destination PB 
CRC Error Rate
A Cyclic Redundancy Check (CRC) is used as a checksum to 
detect alteration of data during transmission. This field displays 
the average CRC (Cyclic Redundancy Check) error rate of 
transmission from the destination Powerline device to the source 
device (as shown in the screen).
The CRC error check is performed after Forward Error 
Correction. If the error rate after FEC error correction is still 
high, then this indicates a lot of noise at all frequencies on this 
section of your Powerline network. Data transmission rates are 
reduced if there is a lot of noise on the line.
Avg. Bits/Carrier
This field displays the average number of bits transferred over 
the connection measured in Mbps. This represents the physical 
rate of data transmission (the PHY rate) which includes not only 
the files sent on your Powerline, but also line overhead required 
to manage your network, such as error correction bits.
The PHY rate is the clearest indicator of the quality of your line. 
• If the PHY rate is close to the HomePlug AV maximum data 
transfer rate, then the quality of this section of the line is 
very high, with very little attenuation.
• If the PHY rate varies between the maximum level and a 
lower level (such as 60 Mbps), there is noise on this section 
of your Powerline. Attenuation is not a factor.
• If the PHY rate is steady at a lower level (such as 80 Mbps), 
this is caused by attenuation and not noise on this section of 
your Powerline.
Avg. SNR/Carrier
This field displays the average Signal to Noise Ratio (SNR) 
measured in dB. Use this to check the amount of noise on this 
part of your Powerline network. The higher the number the 
better the connection quality.
Noise on your Powerline network is usually caused by household 
appliances running on your Powerline network. The motor of a 
refrigerator can create electrical interference. A cell/mobile 
phone recharger which rapidly alternates between on and off 
can also generate noise. Poor cable quality and installation can 
also cause noise. To identify causes of noise on your network, 
disconnect an appliance connected on this part of your 
Powerline network and observe whether this reduces the Signal-
to-Noise ratio.
Table 11   Link Information (continued)
LABEL
DESCRIPTION