Details:

Online indicator for Savi and CS Wireless Series allows other people to know when you're on the phone. You can connect your on-line indicator (OLI) light to your handset lifter or directly into the wireless unit's accessory port on the bottom of its base.

Note: The Savi Office OLI (80827-01) has a straight plug that will not fit the CS bases; instead, you should use a right angle plug.