A PBX telephone system provides the most station features available for station user call processing. Each line may be digital or analog. The PBX system offers the most flexibility in modifying and customizing system performance based on users' needs. The number of lines from the local telephone company would be less than a Centrex environment because users share lines throughout an entire system. This option will have higher up-front costs, but reduced recurring costs and the greatest degree of control available.
Most districts provide services for administrative personnel, faculty members, and students.
The administrative network carries information on budgets, finances, payroll, contracts, schedules, grades, attendance, maintenance, correspondence, Internet access, and so forth. Similarly, the faculty network carries information about grades, attendance, lesson plans, schedules, tests, test results, correspondence, research, Internet access, and so on. The student network carries information on extracurricular activities, schedules, assignments, correspondence, research, Internet access, and so on. This network may often be used by users other than students and be accessed from outside the school-for example, from a public library. This network is the most vulnerable to data and system corruption.