Usage patterns
119番に電話するto call 119 (for an ambulance or fire brigade)
I saw a fire and immediately called 119.
119番で〈物〉を呼ぶto call for an ambulance/fire truck by dialing 119
Since he collapsed, I called an ambulance by dialing 119.
119番にかけるto dial 119
I panicked and couldn't manage to dial 119 for a while.