First off welcome to the forum. NEC requires it's techs to be certified for a reason. What you are trying to do is actually quite easy. The system will assign the next number that is not being taken by a physical port by a station card. Also you have to be aware of your max stations authentication as a system as a whole. If the ext is setup in the numbering plan the only thing you have to really do is program the phone.

Coral Tech
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