Nortel 2001 Installation And Operation Manual page 239

Figure 32
USB Headset Adapter tab
External Lamp Indication tab
Note: The External Lamp is an optional component. It is normally not
included with the USB Headset Adapter and must be ordered separately. The
external lamp is also known as an "In-Use Indicator" lamp.
Nortel IP Softphone 2050
IP Phones Description, Installation, and Operation
Page 239 of 430