By Brandon Mercer

SAN FRANCISCO (CBS SF) — How would you do your job if every modern technlogy you rely on was taken away? No computer, no cash register, no Internet? That was the scene this morning at the Gateway Station Post Office at One Embarcadero Center, as a line of customers, many with tax returns to file, grew longer and longer.

The solitary mail clerk working the morning shift was plunged back into the pre-computer 1970s, with no cash registers working, no electronic postage meters, no electronic scales, and all stamps were affixed painstakingly by hand.

READ MORE: California Gold Rush Town Typifies Labor-Shortage Plight Vexing Businesses

He used his smartphone as a calculator before affixing 8 stamps to a customer’s over-weight tax return, and hand-wrote in the certified mail receipt information, warning that it might not be in the system, then asked for cash as the credit card readers were not connecting.

A box of change sat next to the register, where the fast-moving, but clearly under-staffed man quickly counted out change.

READ MORE: UPDATE: News Crew Security Guard Shot in Oakland Dies From Injuries; Photo of Suspect Vehicle Released

An early morning power outage in San Francisco shut down 30,000 customers’ electricity, and was the cause of the system reset at the Gateway Station.

“Computers affect our lives ever since the advent of the Internet,” said U.S. Postal Service spokesperson Gus Ruiz. “We handle these things as they come up, and they’re trained people. It’s not like we haven’t experienced crisis before.”

MORE NEWS: UPDATE: 2 Men Shot Outside South Bay High School Football Playoff Game

He added, the important thing is, “We’re still open for business.”