ZyXEL Communications P-660HN-F1A, User Manual

Page: 338 / 430

Chapter 23 Diagnostic
P-660HN-F1A User’s Guide
338
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-660HN-F1A 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-660HN-F1A is using to transmit to the ISP.
attenuation downstream is the reduction in amplitude (in decibels) of
the DSL signal coming into the P-660HN-F1A 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-660HN-F1A’s
ATM statistics, DSL connection statistics, DHCP settings, firmware
version, WAN and gateway IP address, VPI/VCI and LAN IP address.
Table 118 Maintenance > Diagnostic > DSL Line (continued)
LABEL DESCRIPTION