San Francisco's 911 system suffered a breakdown late Thursday night, that hampered emergency dispatchers.
The Department of Emergency Management told KTVU, that just before midnight, the dispatch center experienced a "power disruption."
It caused radio terminals and a computer system to go down.
According to a D.E.M. spokesperson, the telephone system remained operational, and dispatchers could still receive emergency and non-emergency phone calls from the public.
Due to the electrical issue, the dispatch center enacted manual-mode protocols.
DIspatchers had to write down on paper the 911 calls, and give the information to a group of "runners."
They passed on the information to a separate group of dispatchers, who then used handheld radios, to contact first responders, to send them to the people who needed help.
Technical support was able to fix the problem, and the system returned to normal by 3 a.m..
Officials wanted to stress that people phoning 911, had their calls and answered.