I am working on a similar setup. All comercial trunking is run through legacy Nortel CO. Stations are being gradually cutover to new CUCM. Only works smoothly if they are decommisioned in the Nortel and routed via vitual numbers over tie trunks by RLI programming. Eventually the legacy Nortel will be shut down and all CO calls routed to the CUCM by SIP trunks.


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