I have a customer that has outgrown a N0616 unit and needs to expand to around 24 phones. He has 4 CO lines. What recommendations do you have?

Question 2, is there a quick and easy way to fix the speakerphone portion of the phones? I have a few that you can hear but not speak on the speakerphone. I was hoping to save the time of sending them out for repair. Thanks,

Doug