An alarm system monitored by security personnel under the owner's control is known as a(n):

The term that best describes an alarm system monitored by security personnel under the owner's control is a proprietary alarm. This type of alarm system is typically managed internally by the organization, which allows the owners to have direct oversight and control over the alarm response. Proprietary alarms can include systems that are monitored by in-house security staff rather than an external agency.

In contrast, intruder alarms are primarily designed to detect unauthorized entry and might not include any specific monitoring component by personnel. Local alarms generally sound an audible alert on the premises but do not notify outside monitors. Central station alarms involve external monitoring by a third-party security service, which is not under the direct control of the owner. Therefore, the distinguishing characteristic of a proprietary alarm lies in the ownership and control of the monitoring process by the organization itself.