So, what makes the time & temperature numbers that I run work? Glad you asked! It's build on an open source piece of software called Asterisk. Asterisk is software that is free to download, install, and use, and is actually intended to be a PBX system. What's a PBX? Well, it's just a fancy way of saying that it's an "office" phone system. It's used around the world in a bunch of different offices and other places for telephone service. I've modified it slightly, with some help from a couple guys I met on Facebook, to make it answer incoming calls, play a short advertisement, then tell you the current time and temperature.

If you call the Salem, IN number at 812-896-8463, the temperature is fed to the system from a temperature sensor located outside my house. If you call the Mitchell, IN number at 812-992-8463, the system has to go out to the internet and get the current temperature from a service as I do not have a location in Mitchell that I can place a sensor. I've found that the service I'm using is fairly accurate though as I've called the number while driving through Mitchell and compared the reading it gives to a reading from my vehicles outside air temperature sensor and they are always either the same or within a degree or so of each other.

The software itself runs on a small computer (an Intel NUC) and connects to a SIP Trunk provider. A SIP Trunk provider is sort of like Vonage, or any other VoIP telephone service that you would get for your home, however, it's specifically designed for customers that are willing and able to provide their own hardware and or software to connect to their voice service. I can handle as many as 25 simultaneous calls coming in to check the time and temperature, not that I get anywhere near that number of calls.