The interviewer would like to know more about the volume of calls you are accustomed to taking, on an average day. If you are an experienced administrator, you probably know this answer off the top of your head. Think about how many hours per day you work, how many lines you handle on a daily basis, and how often you find yourself picking up a new call.
"In my current role I work with three phone lines, and would estimate that I received about five calls per line, per hour. So, on average, I would say that I answer between 100-125 calls per day. In addition to these calls, I also reply to about 60-80 emails and a handful of walk-ins. I am confident in my ability to handle your multi-line phone system."
"I do not have experience with a multi-line phone system; however, I am very tech savvy and am highly confident in my abilities to learn. I understand that you have a strong training program in place as well. I look forward to showing you what I can do!"
"I have worked with up to a 10-line switchboard and have also trained other new administrators on the use of multi-line systems. I consider myself an expert with multi-line systems and do not doubt that I could handle the call volume here."