| 摘要 |
The system of the invention consists of a central office service unit (COSU) connected to a plurality of switching systems via dedicated telemetry trunks or a common channel signaling network such as the CCS7 network. The switching systems are connected to a plurality of inbound-only TIUs located on the customer premise that are in turn connected to customer devices such as utility meters, appliances, security systems or the like. The TIUs are inbound-only that can originate calls but cannot answer calls initiated by the controlling entity. A controlling entity, such as a utility, is connected to one of the switching systems over a customer line such that the controlling entity can be connected to any TIU hosted by the switching systems. The controlling entity requests that an alerting tone be sent by the COSU to a desired TIU. The COSU, as is known in the art, delivers an alert tone through a suppressed ringing connection to the TIU that does not audibly ring the customer's telephone. The TIU does not "answer" this tone by going off hook such that no connection is established and the telemetry call is taken down. While the TIU does not answer the alert tone, the tone alerts the TIU to perform one or more functions such as retrieve data from a utility meter, check the status of an appliance or the like. As an alternative to the alert tone, a digital signal can be transmitted to alert the TIU. After performing the desired function, the TIU is programmed to call the controlling entity and a connection is established between the TIU and the controlling entity. The TIU can then transmit the results of the function to the controlling entity and the controlling entity can download further instructions, programs or the like to the TIU.
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