Pika µFirewall SIP firewall review

A new way to secure your IP-PBX Recently introduced by the well-established Canadian telecoms manufacturer Pika Technologies, the Pika µFirewall offers a novel way to make your Asterisk (or any other SIP-based PBX) more secure. The best way to describe it is as a “SIP Firewall”, but unlike conventional network firewalls, installation is very simple … Read more


RTP pass-through mode in Asterisk

What is RTP pass-through mode in Asterisk? The speech for VoIP calls uses RTP (Real Time Protocol) to get from one end to the other and it is compressed using one of the many speech compression codecs available. Commonly used codecs include G.711 and G.729. When you call someone through an Asterisk PBX, there will be … Read more


Asterisk SLA (Shared Line Appearances) – Part 4

Link to part 3 What is good and what is bad about the Asterisk implementation of SLA? Benefits of Asterisk Shared Line Appearances Replacement of legacy systems: The main reason for wanting to configure Shared Line Appearances in Asterisk is because the Asterisk system is replacing a traditional key and lamp telephone system. However, this … Read more


Asterisk SLA (Shared Line Appearances) – Part 3

Link to part 2 EXTENSIONS.CONF: Setting the Hints used by SLA The SIP SUBSCRIBE/NOTIFY mechanism – what it is and how it works The SIP protocol includes a standardised mechanism to allow any SIP client (an IP phone being an example of a SIP client) to monitor the state of another device. Details are provided … Read more


Asterisk SLA (Shared Line Appearances) – Part 2

Link to part 1 About the examples and conf file samples used in this article The following sections will guide you through the setup of a small Asterisk system using shared line appearances. Each step is explained to show how it works. The dial plan examples will start with a fairly simple configuration and we … Read more


Asterisk SLA (Shared Line Appearances) – Part 1

Terminology and SLA Concepts Terminology We have attempted to use the correct terminology (as recognised throughout the telephony industry) within the explanations on this web page. However, as it is so important to be clear about the meaning of the terminology used here, it seemed like a good idea to set it out explicitly at … Read more