Differences

This shows you the differences between two versions of the page.

--- adsl:troubleshoot [2010/11/26 10:16] – mats
+++ adsl:troubleshoot [2010/11/26 14:00] (current) – mats
@@ Line 25: / Line 25: @@
 If the modem has been in contact with a DSLAM (two or three dots) but could not maintain a connection, or could not transmit data on the connection, then you need to check:
   - VCI/VPI values on the [[:web GUI:Network page#Access type|Network page]] must match your Internet Provider's values.
-  - ADSL mode on the [[:web GUI:ADSL page]] must match the ones used be the DSLAM at the other end of the connection
+  - ADSL mode on the [[:web GUI:ADSL page]] must match the ones offered by the DSLAM at the other end of the connection
-  - ADSL standard on the Advanced [[:web GUI:ADSL page]] must match the ones used be the DSLAM at the other end of the connection
+  - ADSL standard on the Advanced [[:web GUI:ADSL page]] must match the one used by the DSLAM at the other end of the connection
 ===== Training, retraining and disconnecting =====
@@ Line 40: / Line 40: @@
 If this never seems to happen, see the [[troubleshooting:internet_access_problems|internet access problems]] page for how to carry on the troubleshooting.
 It may be a problem with the VPI/VCI settings or some DHCP or PPPoE/PPPoA problems.
+\\
-The ADSL connection, when successfully established, will stay up "forever", as long as the modem is powered on.
+\\
-However, disturbances can happen on the telephone line that may force the modem to drop the link.
+\\
+The ADSL connection, when successfully established, will stay up "forever" as long as the modem is powered on.
+However, disturbances can happen on the telephone line that may force the modem to drop the link and to retune to the apparently noisy line.
 In the ADSL language this is a //retrain//.
-This is visible on the display: the ''**Hi**'', ''**Lo**'' or ''**AC**'' text disappear.
+This is visible on the display: the ''**Hi**'', ''**Lo**'' or ''**AC**'' text disappears and is replaced by one or more dots (see above).\\
-In the [[web_gui:system_log_page|system log]] there is a link down message.
+In the [[web_gui:system_log_page|system log]] there is now a message
+  line(line): Link down.
+accompanied by one or more lines telling, in technical terms, the causes of the link drop. For example:
+  ADSL: local loss of signal error
+  ADSL: local severely errored frames error
+It is not always clear what causes such a disturbance.
+Surprisingly often, the fault is actually to be found at the customer's premises (i.e. inside your own building):
+  * Is the ADSL connector and the [[adsl:start#Splitter|splitter]] properly connected?\\ :!: Generally, the ADSL modem should be connected to the 1:st (main) phone jack to get as clean signal as possible.
+  * Are there more devices, apart from phones, attached to this telephone line, such as fax machines, answering machines etc? If so, try disconnecting them one at a time to see if the problem disappears.
+  * Are there any disturbing appliances in the //very// close vicinity of the modem and its ADSL cable?
+If no obvious source for the disturbance is to be found, and it happens frequently, the Internet (or ADSL line) provider's support should be consulted.
+The advanced user may consider to use the **Force SNR Margin** or even disable the **Retrain** parameter, see the [[web_gui:adsl_page#Advanced|ADSL settings]] page.
+After a link drop the modem will constantly try to establish the connection again, without any user intervention:
+  * If the dots remain on the front panel display, there is a constant disturbance or a broken cable connection that must be fixed.
+  * If the retrain is successful and the link is established, the rolling figure-of-eight plus "''**IP**''" reappears and the modem starts renewing its IP address again, as has been described above.