A special “Bits and Bytes” edition
By Mark Ollig
Sept. 11, 2026
Nearly everyone can recall exactly where they were when they first learned a plane had struck the World Trade Center on Sept. 11, 2001.
At the time, I worked at the TDS Telecom telephone central office in Monticello, Minnesota.
Its Nortel DMS-500 digital switch served roughly 50,000 subscribers and routed local, long-distance and wireless-carrier (cellular) calls.
Remote equipment in St. Cloud, Brainerd, Duluth and Rochester serving subscribers there connected directly to the Monticello switch through multiple dedicated 45 Mbps DS3 “umbilical” links carried over fiber-optic lines
On the morning of Sept. 11, inside the Monticello telephone office break room, a television showed the North Tower of the World Trade Center burning after it was struck at 7:46 a.m. Minnesota time.
Initial reports indicated that a plane might have struck the tower and that it was a tragic accident.
At 8:03 a.m., when the second plane hit the South Tower, it became clear that we were witnessing a coordinated attack on the United States.
At 8:25 a.m. Minnesota time, the Federal Aviation Administration (FAA) ordered a nationwide ground stop, halting all civilian flight takeoffs across the United States. Twenty minutes later, all aircraft already airborne were instructed to land at the nearest suitable airport.
The grounding stranded tens of thousands of passengers at airports nationwide.
At Minneapolis-St. Paul International Airport, Airport Director Tim Callister said the facility normally handled more than 500 flights carrying 90,000 to 100,000 passengers each day.
Another hijacked plane struck the Pentagon at 8:37 a.m., tearing through the western side of the building and causing a massive explosion that echoed across Arlington, Virginia.
At 8:59 a.m., the South Tower of the World Trade Center collapsed.
United Airlines Flight 93 crashed in Pennsylvania at 9:03 a.m.
At 9:28 a.m., the North Tower of the World Trade Center collapsed.
My role involved programming telephone traffic routing for digital switches like the DMS-500 and managing high-demand calling patterns during the crisis.
Newspaper accounts from that day reported that nationwide call volume surged as high as 400% above normal, overwhelming the nation's telephone infrastructure and pushing it to the breaking point.
When demand exceeded trunking capacity, calls were blocked, resulting in fast busy signals, "all circuits are busy" messages, or recordings asking callers to try again later.
Inside the Monticello central office, our network traffic at times approached that same level.
The Duluth News Tribune reported that both telephone and cellular systems in the Twin Cities were jammed, causing frequent call disruptions.
The Associated Press reported in the Sept. 12, 2001, edition of the Winona Daily News that most calls to and from New York would not go through.
The Twin Towers housed Verizon local exchange equipment and antennas that carried millions of calls daily.
Sprint reported that the loss of leased landline equipment beneath one of the Twin Towers blocked about 75,000 long-distance calls.
Carriers rerouted traffic around the damage, but call volumes were unlike anything the network had handled before, disrupting telecommunications across much of New York City.
The AP also reported that internet traffic slowed and major news sites were overwhelmed as people sought information online. Email, by contrast, proved more reliable for many who could not get through on calls.
America Online's Instant Messenger service was sporadic in New York, and its dial-up connections were constantly busy.
AP also reported that Rebecca Amelio, a University of Wisconsin-Madison student whose family lived near New York City, "tried repeatedly to call and couldn't get through." Eventually, her family reached her.
Laura Steele of Milwaukee spent six hours trying to learn whether her father, who worked near the Pentagon, was safe. "All the phones were down," the Associated Press reported her saying. She finally found out he was unharmed.
At St. Mary's Hospital in Superior, WI, switchboard operator Pam Salus said the hospital received many calls from people wanting to donate blood. "They heard that they need blood and they heard places are doing blood drives," she said.
The Minneapolis Star Tribune reported that a Minneapolis mother couldn't reach her daughter in Manhattan by landline or cellphone; however, her daughter eventually reached her while the second tower was collapsing.
The Star Tribune Extra reported that Minneapolis-St. Paul International Airport shut down, the IDS Center evacuated, and the Mall of America closed for the day.
Gov. Jesse Ventura activated the state emergency center through Public Safety Commissioner Charlie Weaver and stayed in contact with the FBI and Secret Service.
Ventura said Minnesota would remain on high alert until officials identified those responsible, and he expected the National Guard to stay on heightened standby through the weekend.
"We are experiencing one of the most stunning events of our lifetime," Ventura said, adding that people needed to gather their strength because "it's not over yet."
He added, "This is as significant as the attack on Pearl Harbor. Maybe more so because in Pearl Harbor, we knew who the enemy was."
Every FBI agent in the Minneapolis office was placed on standby for instructions from Washington.
The FBI, Secret Service, Minnesota Department of Public Safety, Minneapolis police, and Hennepin County officials coordinated preparations for a possible local response.
Minnesota State Rep. Rich Stanek noted that a Hennepin County Sheriff's emergency response center was ready within two hours of the attack.
The Minnesota State Duty Officer line managed hundreds of calls per hour on Sept. 11 and 12, with a sharp increase in mobile 911 calls.
A statewide terrorism consequence management committee met with key utilities to focus on protecting resources like water, food, fuel, and phone services.
Nationally, Verizon reported call volumes at twice normal levels in New York and Washington, and Cingular reported a 20 percent networkwide increase, according to RCR Wireless.
CNN reported that officials urged the public to stay off phones so emergency calls could get through.
We were told the FBI was concerned that terrorist sleeper cells in American cities, including Minneapolis, could be activated and attempt to seize or disrupt critical communications facilities.
The FBI advised telephone offices to secure their facilities, as breaches could disrupt emergency services and public communications.
We restricted access to the Monticello central office, the DMS facilities in St. Cloud, Brainerd, Duluth and Rochester, and the TDS Telecom exchange in Winsted.
At around 10 p.m., I left the telephone office and noticed the night sky was clear. No planes were making their approach to MSP, as I would normally see from there.
Commercial flights began returning Sept. 13, 2001, under heightened security, with broader service resuming Sept. 14.
On Sept. 13, 2001, FCC Chairman Michael Powell praised the nation's telephone carriers for keeping the network running after the attacks.
Starting Sept. 27, the Minnesota National Guard posted armed soldiers at airports in Minneapolis-St. Paul, Duluth and Rochester.
On Oct. 4, 2001, Qwest CEO Joseph Nacchio told the Senate Governmental Affairs Committee that his company was strengthening its network against physical and cyberattacks.
He emphasized that September 11 had changed the acceptable level of risk, necessitating new approaches to redundancy and to single points of failure.
On Oct. 15, a joint House hearing in Minnetonka examined state readiness with testimony from the FBI's Minneapolis office, Minnesota's U.S. attorney, and Hennepin County Sheriff Pat McGowan.
Those precautions secured our offices and foreshadowed the infrastructure-protection mindset that followed Sept. 11.
Most Americans remember Sept. 11 through television images: planes striking buildings, towers burning and collapsing, and people trying to understand the day in real time.
We monitored the crisis as it unfolded and kept our part of the telephone network working, ensuring calls could get through.
The Sept. 11, 2001, terrorist attacks claimed 2,977 lives, including passengers and crew aboard four hijacked aircraft, first responders and military personnel at the Pentagon, and civilians at the World Trade Center. United Airlines Flight 93, the fourth hijacked plane, crashed in a field outside Shanksville, Pennsylvania, killing all 40 aboard.
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| ChatGPT generated these images based on my article on 9/11, as we worked inside the Monticello telephone office. |
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| CNN website front page from Sept. 11, 2001 |