From Contact; Call From User - Dahua Technology VTH2421F Series User Manual

3.2.3.2 From Contact

Procedure
Step 1 Select Call > Contact.
Step 2 Select the one you want to call.
Step 3 Tap

3.2.4 Call from User

When receiving calls from other VTHs, the following interface will be displayed.
Figure 3-7 Calling
Figure 3-8 Call in progress
to start.
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