Introduction

With Asterisk and the flexibility it offers, you can do some truly amazing things. With a stock configuration, only using what Asterisk has built in, you can build systems that do some really nifty stuff. If you throw the power of AGIs (Asterisk Gateway Interfaces) into the mix, you can write customized applications that might be difficult to accomplish with other VoIP systems.

Most AGI examples are typically written to take advantage of external resources that Asterisk itself might not have direct access to, or know how to deal with. For example, AGIs have been written to look up ISBNs (book numbers), ANACs (Automatic Number Announcement Circuits) that look up a telephone number information from external sources, text-based games, and IDSs (Intrusion Detection Systems) for monitoring.

We can take the power of AGIs a bit further to interface Asterisk with actual hardware. For example, security cameras, electronic door locks, and card readers to name a few. Creativity is the key.

If you can interface with the hardware externally and interact with it, odds are you can come up with some means to write an AGI to pass that information back.

Serial

To start off, we ll touch on serial communications yes, that old communications method you used with a modem to connect to the Internet. Even though it s old, traditional serial is used to communicate with room monitoring equipment, magnetic card readers, robotics, environmental control systems, and various other things. It s used where high-speed bandwidth isn t important, but getting data and...