NEC UNIVERGE SV8100 Features & Specifications Manual page 978

Issue 5.0
Terminals indicate TANDEM IN USE in the display and single line telephone users hear a busy
signal when the handset is lifted.
To cancel Tandem Ringing:
1. Dial 744
-OR-
Press the Tandem Ringing key (Program 15-07 or SC 851: 80).
2. Dial 0 to cancel the feature.
1 - 968
UNIVERGE SV8100
Tandem Ringing