Telephony
This section of the site is about Telephony, the sending of audio data over a variety of technologies.
The Asterisk RPMs page contains details of the Asterisk RPM repository for CentOS/RHEL 6 & 7 hosted here.
The Philippines Numbering/Dial Plan page contains information about the numbering system in the Philippines along with an Asterisk dialplan extract that can be used to implement PSTN connectivity using Asterisk in the Philippines, this page has been created due to the lack of publicly provided information by the telcos in the Philippines and the NTC, the telecommunications regulator in the Philippines.
The Asterisk SIT detection page contains information on and a proof of concept implementation of SIT (Special Information Tone) detection in Asterisk in the app_dial dialplan application that allows the detection of SIT in early media provided through any technology. Asterisk currently is only able to do limited in-band progress detection on DAHDI channels, in most cases this is not a problem as most progress feedback is provided out of band, however, in the PSTN early media is used in many cases to provide user friendly messages as to why a number cannot be reached and access to the PSTN is more and more being provider over VoIP. The result being that an Asterisk based PBX, if placing a call without a person receiving the early media, will wait until it's timeout is reached or the remote end terminates in the event of an unreachable number. As there are many potential situations the could lead to a call being placed without someone receiving early media, this has a significant potential to cause problems. E.g. a call is routed to someone's desk and their home phone with a fall back to voicemail in the event of a call going unanswered, due to a network problem, the call can not reach the home phone so the provider delivers a message with SIT as early media, the caller will have to wait for the call to timeout before being passed to voicemail. The proof of concept provided is similar to something I wrote a few years ago that was in production handling approximately 100000 calls per day, but as I had to reimplement the solution here from scratch, this code has not had anywhere near as much testing.