Years ago, this question was about how to control use of company phone systems and company time on personal phone calls. Sounds like eons ago, doesn’t it? However, the rules for managing excessive texting or other personal use of cell phones during work hours are basically the same.
A well-crafted company (or departmental) policy needs to be promulgated and then enforced. The key will be consistent enforcement. If someone violates the policy, he or she should be disciplined as employees are for other policy infractions (e.g., verbal warning, written warning, final warning, termination).
An effective way to reinforce this policy -- assuming that use of cell phones is a significant problem -- is to include in the policy that at the written or final warning step of the disciplinary process -- whichever the employer prefers -- the employee will be required to surrender his cell phone during working hours.
Of course, as always, do not put forth any policy that you do not intend to enforce uniformly. Doing that only erodes respect for management. Here is a sample policy:
Personal Use of Cell Phones, Computers, and PDAs at Work
While at work, employees are expected to refrain from excessive personal use of cellular phones, computers and PDAs. Personal calls, personal instant messaging, personal text messaging or tweeting during the work day -- regardless of whether the equipment used is company-provided or not -- interferes with employee productivity and is distracting to others. Employees are at work essentially to provide value to the company. They are expected to limit personal interactions during work time and make personal calls and/or send personal text messages, tweets or instant messages on non-work time and to ensure that friends and family members are aware of this company policy. The company is not liable for the loss of personal cellular phones, PDAs or other personal electronic equipment brought into the workplace.