Installing and Configuring Asterisk
Asterisk is the standard open-source PBX solution.
Installing Standard Asterisk
Asterisk, being a project of larger scope and greater age than OpenBTS, is not something that should be documented in great depth here. Instead, there are numerous existing pages online detailing the specifics of this complex piece of software. This page, for instance, details the process for installing Asterisk on numerous different platforms.
For most simple installs, we suggest just installing Asterisk from the main software repository. On Ubuntu:
sudo apt-get install asterisk
Standard asterisk does not not need any configuration to handle calls; they all come into an external context. For higher level-functions (e.g., routing), you may need to install hooks into the subscriber registry.
Installing Asterisk Real-Time
The basic asterisk system is sufficient for simple testing of the OpenBTS system. However, it does not support secure connections, as all communications go through the external context. Similarly, Asterisk is unable to dynamically route calls without the Subscriber Registry, If you need any of these features, you will need to install Asterisk Real-Time which pulls all of it's needed information from a set of connected databases. This is detailed here.