ZyXEL Communications P-2602HWLNI User Manual

 Chapter 30 Diagnostic

P-2602HWLNI User’s Guide

DSL Line Status Click this button 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 ZyXEL Device 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 ZyXEL 

Device is using to transmit to the ISP.
attenuation downstream is the reduction in amplitude (in decibels) of the DSL 

signal coming into the ZyXEL Device 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 button 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 button to display information and statistics about your ZyXEL Device’s 

ATM statistics, DSL connection statistics, DHCP settings, firmware version, WAN 

and gateway IP address, VPI/VCI and LAN IP address.

Table 182   Diagnostic: DSL Line (continued)