ZyXEL Communications ADSL2+4 User Manual

Page of 272
Chapter 20 Diagnostic
P-660H-T1v3s User’s Guide
196
DSL Line 
Status
Click this to view statistics about the DSL connections.
noise margin downstream is the signal to noise ratio for the 
downstream part of the connection (coming into the P-660H-T1v3s from 
the ISP). It is measured in decibels. The higher the number the more 
signal and less noise there is. 
output power upstream is the amount of power (in decibels) that the 
P-660H-T1v3s is using to transmit to the ISP.
attenuation downstream is the reduction in amplitude (in decibels) of 
the DSL signal coming into the P-660H-T1v3s from the ISP.
Discrete Multi-Tone (DMT) modulation divides up a line’s bandwidth into 
sub-carriers (sub-channels) of 4.3125 KHz each called tones. The rest of 
the display is the line’s bit allocation. This is displayed as the number (in 
hexadecimal format) of bits transmitted for each tone. This can be used 
to determine the quality of the connection, whether a given sub-carrier 
loop has sufficient margins to support certain ADSL transmission rates, 
and possibly to determine whether particular specific types of 
interference or line attenuation exist. Refer to the ITU-T G.992.1 
recommendation for more information on DMT. 
The better (or shorter) the line, the higher the number of bits transmitted 
for a DMT tone. The maximum number of bits that can be transmitted per 
DMT tone is 15. There will be some tones without any bits as there has to 
be space between the upstream and downstream channels. 
Reset ADSL 
Line
Click this to reinitialize the ADSL line. The large text box above then 
displays the progress and results of this operation, for example:
"Start to reset ADSL
Loading ADSL modem F/W...
Reset ADSL Line Successfully!"
Capture All 
Logs
Click this to display information and statistics about your P-660H-T1v3s’s 
ATM statistics, DSL connection statistics, DHCP settings, firmware 
version, WAN and gateway IP address, VPI/VCI and LAN IP address.
Table 60   Maintenance > Diagnostic > DSL Line (continued)
LABEL
DESCRIPTION