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WCM1100 / WCM3100 / WCM-Serial / LHM1000 / LVM2000 User Manual
76-02-082 Rev N
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5.9.1.6 WAN Port
The WAN port supports the following loops.
5.9.1.6.1 WAN Remote Loop
In order to test the WAN circuit a remote loop may be requested by sending a loop up
command to the remote unit. The Loop Up command is sent in place of the WAN payload
and consists of a repetitive bit pattern. When the remote device receives the loop up
command request it will apply a loop, looping the receiver back to the transmit, ie a loop
facing the unit requesting the loop, as shown below:
If Phy Loops are disabled, then when the RL loop is requested, the WAN port is
disconnected from the VCG to prevent any live LAN traffic being looped back. When a
loop is applied, in band management access to the remote unit will be lost, however the
loop up/down are physical layer commands and will still be received at the remote unit.
If Phy Loops are enabled, the WAN port will NOT be disconnected from the VCG so LAN
traffic will pass and be looped
The RL Loop Up command is sent for 5 seconds, during which time the UI will display TX,
before assuming the RL state. The Remote unit will indicate a loop is applied by
displaying ROL.
Once testing is complete, the loop may be removed by selecting NONE. At this point the
Loop Down command will be sent for 5 seconds, again TX will be displayed. The remote
unit will remove the loop on receipt of the loop down command.
5.9.1.6.2 LL, Local Loop
When Phy Loops are enabled, a Local loop (Loop transmit back to receive) may be
applied to the WAN port.
