NEC SL1100 Group Listen

Group Listen
Group Listen permits a Multiline Terminal user to talk on the handset and have their caller’s voice broadcast over the telephone speaker. This lets the Multiline Terminal user’s co-workers listen to the conversation. Group Listen turns off the Multiline Terminal handsfree microphone so the caller does not pick the co-worker’s voices during a Group Listen.
•An extension in the headset mode cannot use Group Listen.
•Group Listen is not available to Single Line Terminals.