Program the i2004 pretty much the same way you do the 3904. It will be a different TN, of course, but when you out the 3904 that will make that DN available for use on the i2004. If you have other i2004s already built (and these are not ACD phones) just out the 3904, copy one of the other i2004's and then change the name and whatever else you need.
PRINT the TNB for the 3904 before outing it so you will have a record of what CLS and other settings you want to follow...
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"Dyin'? Boy, He can have this little life any time He wants to. Do Ya hear that? Are ya hearin' it? Come on. You're welcome to it, Ol' Timer. Let me know You're up there. Come on. Love me, hate me, kill me, anything. Just let me know it... I'm just standin' in the rain talkin' to myself." Cool Hand Luke