I just was dropped a new ISDN E1 voice circuit. The site is in South America and I was researching what supplimentary protocol to use and I also came across some features that need to be turned on in CM. One being ISDN Feature Plus. This is flagged to 'n'... but ISDN PRI is set to 'y'. Do I need this ISDN Feature Plus and if so do I have access to turn it on?