2 Replies Latest reply on Aug 20, 2012 4:18 PM by manojkumar305

    PRI to Cisco CME

    manojkumar305 New Member

      We are having issues with keep the PRI circuit up


      Adtran 908e is intermittent, tried to use the alternative T1 options on Adtran 908e, same results.


      Clock jumps from line to internal and when it goes to internal, it goes down. Relevant configuration below - any help is appreciated



      interface t1 0/4

        description Skybeam PRI

        fdl att

        tdm-group 1 timeslots 1-24 speed 64

        no shutdown



      interface pri 1

        description pri 1

        isdn name-delivery display

        connect t1 0/4 tdm-group 1

        role network b-channel-restarts disable

        no shutdown



      isdn-group 1

        connect pri 1


      voice trunk T01 type sip

        description "JKHKHKHK"

        match dnis "XNXX-NXX-XXXX" substitute "011XNXX-NXX-XXXX"

        sip-server primary x.x.x.x

        no registrar require-expires


      voice trunk T02 type isdn

        description "Cisco"

        resource-selection linear ascending

        connect isdn-group 1




        no nls

        rtp delay-mode adaptive



      voice grouped-trunk SIP

        trunk T01

        accept $ cost 0

        accept NXX-NXX-XXXX cost 0

        accept 011-$ cost 0

        reject NXX-976-XXXX



      voice grouped-trunk PRI

        trunk T02

        accept $ cost 0


        • Re: PRI to Cisco CME
          david Employee



          Thanks for posting!  Any automatic timing change in the unit is the result of the timing source being lost, or the T-1 going down in this case.  Generally speaking, the T-1 clock for the Total Access 900 series units should synchronize to a carrier-facing T-1 or be set to internal if the unit has an Ethernet port facing the carrier.  The Cisco CME should be set to synchronize its clock to the T-1 clock it receives from the Adtran unit.  Typically this would be called "line" or "network" timing on the PBX.


          You should first always verify that T-1 framing and coding settings match up.  Then verify the timing settings above.  If you take errors on the Adtran unit, we would typically plug the port into a loopback adapter to verify the port runs without errors to itself.  If it takes errors when connected to the Cisco, you may want to attempt to adjust the LBO settings on that port.  Below is an example.


          interface t1 0/3

            lbo long -15


          It is rare, but occasionally I see this attenuation help clear up synchronization issues on the connected device.  If you are unable to prevent the PBX from dropping the T-1 or sending an alarm of some kind, we would be glad to assist you further.  However, you may need to place a T-1 test set between the two units to check for problems with voltage or frequency.  In particular, I would check the frequency the Adtran unit is sending out and verify the PBX is sending back T-1 framing at that same frequency.