I am trying to add a Nortel Networks NTAB4213 Audio Conference phone to our Nortel Compact ICS 7.1 system. I get a dial tone, but get a busy signal when trying to dial a number. The sheet of paper that came with the phone mentions assigning 2 intercom lines, the prime line as intercom, and setting Handsfree Answerback as NO.

I assigned 2 lines to this phone, the 2 lines we have, as Appear& Ring, Prime Line as I/C. However, the next option for this set is listed as Intercom Key. I changed it to 2, dont know if a particular number for this key matters, but when using the phone I press the number 2 after I hear the dial tone and it doesnt work. I have also changed the Handsfree Answerback to NO.

Does anyone have experience with adding this conference phone?