On-Hold Plus TEHMA Music-on-Hold
Used with OHP4500 and OHP5500. In order to achieve true "hold button" activation, On-Hold Plus created a small module called a TEMHA (telephone extension hold music activator). This line powered activator sends a signal down the phone line telling the OHP 4500 unit whether the phone is on-hold. Only phone extensions with a TEHMA can put a call on-hold with the phone's hold button. Phones without a TEHMA can put a call on-hold by pressing the star key twice and then pressing the phone's hold button.