NEC Electra Elite IPK II Features And Specifications Manual page 272

Document Revision 1
9. Dial the mode number in which the key will delay ring.
1 = Day 1
2 = Night 1
3 = Midnight 1
4 = Rest 1
5 = Day 2
6 = Night 2
7 = Midnight 2
8 = Rest 2
10. Press the Speaker key.
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Electra Elite IPK II
Delayed Ringing