Does talaq by phone call or video call take effect?

Yes; clear words of talaq by phone or video call take effect just like words spoken face to face, because the husband's voice is heard directly.
The presence of the wife or witnesses is not a condition for a valid talaq. However, the question of proof arises: the wife must prove the voice was her husband's and what words were said. Recordings, witnesses who heard it or the husband's admission can help.
In Malaysia, such a talaq is still regarded as outside court, so it must be reported for validation. The court will summon both parties. See talaq & divorce.