About the Ring Detector Cable
The external ring detector cable should be used with if your telephone's speaker is not located beneath the hand receiver. While you shouldn't need this cable if your phone's speaker is located beneath the hand receiver, you may want to use it if your headset does not notify you when the phone rings.
How to Install
Your HL10 with ring detector cable might look like the picture below. Please note that your setup might be slightly
different depending on your telephone model.