Federal workers could soon be asked to turn in their government-issued BlackBerries and iPhones.

That's because if the government shuts down next Tuesday, furloughed federal workers could be violating the law if they do something as simple as check their work e-mail.

The Antideficiency Act, passed by Congress during Chester Arthur's administration, prevents non-working federal employees from doing any job-related functions during a shutdown if the government cannot pay for it.

The White House budget office made clear last week that employees on furlough during a shutdown can't touch their government-issued mobile devices, or even use home computers or laptops to access work email.

Related: How a government shutdown hurts Main Street

But in the age of ubiquitous communication, how do you even enforce a no-cell phone ban?

The truth is, no one really knows yet. In the last shutdown of 1996, the Palm Pilot was about as advanced as handheld devices got.

The Office of Management and Budget has left it up to the various federal agencies to figure out how to carry out its edict.

In 2011, when the government came close to a shutdown, the Department of Housing and Urban Development said it would allow employees to keep government-issued BlackBerries (BBRY) and laptops on the condition they didn't use them. But the House of Representatives had planned to order furloughed employees to turn in their BlackBerries, laptops, and even cell phones, and to turn on "out of office" messages.

Now, with a shutdown looming just a week a way, the HUD, House, and the IRS have said they're still crafting their contingency plans, including how to handle websites and mobile phone use.

Federal worker union representatives say it doesn't matter what the government decides on BlackBerry use.

"When a federal employee gets furloughed because of a government shutdown, the last thing they're worried about is whether they can turn on their laptop or Blackberry; they're worried about paying the mortgage and putting food on the table," said William R. Dougan, national president of the National Federation of Federal Employees.

Shutdown expert John Cooney said a short shutdown lasting a few days may have little impact and agencies may not require staff to turn phones in.

"If it's a long shut down, the agency could collect cell phones from employees," said Cooney who helped craft the modern day shutdown plan for the Reagan White House.

Related: Are Social Security payments at risk?

One potential problem: The budget office says agencies can't rely on work email to alert employees to go back to work, when a shutdown ends. The agencies will have go back to old-fashioned communication to get furloughed employees to return to the office via unconventional tools like calls to personal phones, television, radio, Facebook and Twitter.

Of course, federal employees in critical jobs will continue to work, and also use their smartphones to carry out their "essential functions." They include some senior managers, lawmakers and workers who are needed to protect life and property.

They also include the President, also known as the E-mailer-in-chief, and a government employee with a critical job.