Introduction to Automatic Remote Dialers
Just what is an automatic remote dialer?
An automatic remote dialer is a device that monitors conditions at a remote site and, if an alarm condition develops, will alert people (or data processing equipment) at other remote locations. The local conditions may be monitored by a variety of sensors to keep track of the environment, process parameters, intruders, etc. Inputs may include one or more of the following: temperature sensors, sound pickup, AC power sensors, 4-20 mAdc process signals, voltage analog signals, or dry contact closures. These inputs may be sensed on an alert basis in which an alarm condition generates an action, or a non-alert basis in which the input is monitored without any alarm limits. If an alarm condition develops, remote sites will be dialed and a warning message in English wil be trasmitted when the remote phone is picked up. If the remote phone number is not answered, the automatic dialer will successively try additional numbers entered into the system. The number of phone lines that can be called will vary from one system to another. In most cases, the waiting time before a new number is tried can be programmed to suit preferences.In addition, some automatic dialing remote monitors will store data acquired by their inputs and transmit them when interrogated by phone or by computer interface. Some units will continuously transmit monitored data from their inputs.
How can I choose among the various auto dialers?
The cost and features vary widely among the units available. Some are easy to set up and have limited range of capabilities. Others require use of audible or visual, menu-driven, software. Some provide the ability of using a programing language, such as "C", to implement a truly specialized set of application conditions. Regardless of whether the auto dialer supports a flexible programming language or a very simple set of structured menu selections, most can be set up at the local site or remotedly by use of serial communication ports, modems, or data communication lines.
