Philadelphia's Unified Dispatch Unit is shoehorned into a nondescript office on the seventh floor of City Hall.

With its stained drop-ceiling panels and fluorescent lighting, the office hardly looks controversial. Duct tape covers tears in the industrial-gray carpet. On one dingy buff-colored wall is a map of the city. On another is a poster: "Lack of planning on your part does not constitute an emergency on my part."

Managing Director Richard Negrin describes it as the city's nerve center, a hub that allows Philadelphia's public servants to communicate with one another day or night.

But City Controller Alan Butkovitz has labeled it something more nefarious: Mayor Nutter's "secret VIP call center," where the well-connected get special treatment, a characterization Negrin describes as "ridiculous."

A visit there on Thursday found a pair of dispatchers seated in front of computer monitors, phones at the ready, as they settled into their 3-to-11-p.m. shift. Ruby, who declined to give her last name, was busy arranging conference calls among city administrators. Steve, who also preferred to give only his first name, was dealing with the report of an out-of-service traffic signal in the city's northwest.

For the next eight hours, based on statistics the city keeps, they could expect to handle, on average, a call every three minutes. The overwhelming majority of those calls, the dispatchers said, are from city or court employees on matters ranging from downed trees to gas leaks to flooded streets to lawyers needing to speak to judges in critical cases.

And, yes, they said, they occasionally hear from VIPs - even an ex-mayor.

"Of course," Ruby said. "Mayor [Ed] Rendell might call from time to time because he is very familiar with us. But if somebody calls, they are calling about something urgent."

Which was why both dispatchers said last week they felt unfairly maligned by Butkovitz.

"That was a very irresponsible statement," Ruby said. "This unit is vital to our citizens. We make sure that their streets are clear, their manholes are covered, their potholes are filled, their collapsed buildings are reported. The controller minimized our function, and that is disheartening to me."

The Unified Dispatch Unit has existed in some form or other for more than 40 years, according to Nutter spokesman Mark McDonald.

The unit acts as the city government's reptilian brain, instinctively responding to distress signals and summoning help. In times of crisis, its dispatchers contact officials and coordinate departments. They field calls night and day on a host of concerns, big and small, and notify the appropriate departments.

If a street is closed, for instance, unit dispatchers notify SEPTA as well as the Police and Fire Departments. Reports of power outages are forwarded to Peco. PGW gets reports of gas leaks. Fire and burglar alarms in all city buildings are monitored.

"If a mouse crosses a carpet in one of our buildings, we hear about it," Steve joked.

The unit's work was largely anonymous until Butkovitz questioned the reason for its existence.

On Sept. 17 in a letter to Nutter, Butkovitz described the unit as "an exclusive City Hall hotline for the well-connected" that was squandering hundreds of thousands of tax dollars in overtime - $164,000 in 2013 alone, by his count. He said the money might be better used to expand the hours of the city's 311 system for average folks.

Butkovitz, who is considering a run for mayor next year, has declined to say how he reached that conclusion, rebuffing reporters' requests by saying, "I'll reveal my sources when you reveal yours."

Negrin called Butkovitz's assertions bizarre and troubling.

"The controller's use of inflammatory terms such as secret and alleging that there are better services for well-connected people funded by public dollars is a serious allegation and should not be made so irresponsibly," he said. "There is no 'secret' group of people working away all night long in City Hall, for any reason, let alone some ridiculous hotline for 'connected' persons."

Negrin said the Unified Dispatch system was intended solely as an internal communication system but acknowledged that elected officials past and present were aware of how it works and had been known to make use of it.

"The reality is, every city councilperson has my cellphone number," he said. "They don't need a special hotline. They can call me any time they want."

In an interview Friday, Butkovitz defended his characterization of the unit while offering a rather broad definition of "VIP" to include the very city administrators and employees who were intended to use the Unified Dispatch system daily in their jobs.

"I think when the administration decides who gets the phone number and who doesn't, that is VIP treatment," he said. "Look at it this way, somebody who is not a city employee has just as much potential of seeing something that may require urgent action and should have that number."

Butkovitz noted he had not been given the number.

He contended the flap over his characterization of the unit had obscured his key point: that the typical Philadelphian's access to service was limited to the 12-hour weekday shifts worked by the 311 staff.

"When the 311 system was implemented, its stated purpose was to make sure there was no privileged class or special treatment for certain people," he said. "The administration needs to live up to what they told everybody."

By extension, then, "the privileged class" in this instance includes city employees who must serve Philadelphia around the clock.

The Unified Dispatch Unit is overseen by Raymond Hayling, the city's deputy chief innovation officer. He says when he first heard Butkovitz allege a "secret VIP call center," it never occurred to him the controller was referring to his operation.

"That characterization would not lead me to believe they were talking about this unit," Hayling said.

Asked whether he was troubled by the description, Hayling said, "I'm a professional, so we deal with it."

Then he continued.

"What really bothers me is you minimize what they do," he said, motioning to his two dispatchers. "What they do is terribly important. The way I would describe it, if we were at war, they might not be fighting, but they are making sure you have ammunition when it is running out. They are the ones in the background making sure you can do your job."