In order to achieve true "hold button" activation, we created a small module called a TEHMA (telephone extension hold music activator).
This line-powered activator sends a signal down the phone line telling the MOH 500e unit whether or not the phone is on hold.
Only phone extensions with a TEHMA can put a call on hold with the phone's hold button.
Extensions without a TEHMA can put a call on-hold py pressing the * key twice.
Phones without a TEHMA can put a call on hold by pressing the star key twice and then pressing the phone's hold button.