Siemens Information & Communication Networks, Inc.

Michael Worsham

Matthew T Dean

A private branch exchange is provided having the capability of receiving external alarms via the standard telephony line or trunk interfaces. According to one embodiment, a PBX 200 includes a switching control circuit 202 having line monitor 212 and DTMF 210 capabilities. The switching control circuit 202 is coupled to a central processing unit 204 which in turn is coupled to a memory 206. The memory 206 stores a database 208 identifying a predetermined number of telephony trunk 214 and/or line input/output circuits 218 over which external alarms are to be reported. The CPU 204 identifies an external alarm contact closure as a fault on the telephone line or trunk, thereby insuring proper identification of the location of the alarm.

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Campbell, CA, United States of America

Michael Worsham