Looking at the poll results so far, it seems that most of us reacted to what we considered to be an "unfair" policy, but as the course materials point out, an opinion that something is "unfair" does not mean that it is illegal.
After reading the course materials, I would change my responses to the poll. I believe that this would fall under the category of "company policy" and would be allowable under the law, as long as the cost of purchasing and using a phone or communication device did not cause the employees' wages to fall below the federal- or state-mandated minimum. The policy does not appear to be discriminatory based on any protected classes. The policy could be considered comparable to employees being required to purchase uniforms for their work. Although it would be legal, the policy may not be very popular, and might ultimately result in a backlash in terms of employee morale, effort, and longevity with the company.
In addition to determining whether the cost of the communication device would decrease the net pay below minimum wage, it would also be important to get additional information about the policy in terms of accessibility of employees beyond the regular work day and work week, since the understanding of the employee writing the email is that employees would now be expected to communicate 24 hours a day, 7 days a week. This could potentially pose some issues for non-exempt employees in terms of a normal 40 hour work-week. Would there be an expectation that employees would work beyond 40 hours a week? Would there be a workload reduction to compensate for the extra time in the evenings or on weekends? Would they be paid overtime for any time spent beyond 40 hours? What are the consequences for employees who are either unavailable or unwilling to work outside of the normal 40 hour work week? Is this policy enforceable?