Troubleshooting guide

If you are not sure what pins on your wall jack are active, ask your ISP.
Do you have the correct power supply for the Cisco 827?
If you have verified that your DSL cable is good and that you have the correct pinouts, the next step is to
make sure you have the correct power supply for the 827.
Note: The 827 does not use the same power supply as other 800 series routers.
To determine if you have the correct power supply, on the back of the power adapter look for Output +12V
0.1A, −12V 0.1A, +5V 3A, −24V 0.12A, and −71V 0.12A. If your power supply is missing the +12V and
−12V feeds, then it is for a different Cisco 800 series router and will not work on the 827. Note that if you use
the wrong power supply, the Cisco 827 will power up but will be unable to train up (connect) to the ISP
DSLAM.
Is the DSL operating−mode correct?
If everything up to this point in the Layer 1 troubleshooting procedure is correct, the next step is to make sure
you have the correct DSL operating mode. Cisco recommends using dsl operating−mode auto if you are not
sure what DMT technology your ISP is using. The commands to configure operating−mode autodetection are
as follows:
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface atm 0
Router(config−if)#dsl operating−mode auto
Router(config−if)#end
Router#write memory
Is the circuit tested/provisioned correctly?
Obtain this information from your ISP or telephone company.
Layer 2 Issues
Do you have the correct PVC values (VPI/VCI)?
With a PPPoE deployment there is no easy way to dynamically discover your Permanent Virtual Circuit
(PVC) virtual path identifier/virtual channel identifier (VPI/VCI) values. Contact your ISP if you are not sure
of your PVC values.
Are you receiving data from your ISP?
If you have the correct PVC values, the next step is to verify that you are attempting to negotiate PPP with
your ISP. To do this, issue the command show interface atm0 and check the input and output packets.
Router#show interface atm0
ATM0 is up, line protocol is up
Hardware is DSLSAR (with Alcatel ADSL Module)
MTU 4470 bytes, sub MTU 4470, BW 128 Kbit, DLY 16000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL5, PVC mode
Cisco DSL Router Configuration and Troubleshooting Guide