Any unused DN can be an ACDN, it just depends where you program it.
In LD 10 or 11 you can find out:
ld 10:
req=prt
type=ludn
this will give you a list of all available numbers, if it shows just a 7 then every number after that digit is available, ie 7000-7999 (using 4 digits only). If it shows 72 then all 72xx numbers are available, 7200-7299.
Then just go to ld 23 and add it.
ld 23:
req=new
type=acd
then build it accordingly.
JohnThePhoneGuy
"If I can't fix it, it's not broke!