VTech IS7121-22 User Manual page 26

Getting started
Installing the doorbell with an existing wired doorbell
Option 2: Ring the rear doorbell of the existing wired doorbell and the IS7121
doorbell simultaneously.
• If you do not connect domestic power supply nor install AA batteries to
the IS7121 doorbell, only the existing wired doorbell will ring when being
pressed.
Follow Step 6 to Step 7 in Doorbell installation on page 17 to complete
5.
the installation.
Angle
Adjustment
View View
Right Left
Chime/buzzer of wired doorbell
Rear Trans Front
21
Transformer