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Developers

Asterisk in depth.

Asterisk is the open-source PBX that a large share of the world’s phone menus still run on. These guides cover it the way an operator needs it, citing the Asterisk documentation and source for every behaviour described.

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The guides

Asterisk · 25 min read
Asterisk architecture and PJSIP, for the people who will run it.
How Asterisk works for people who run it: channels, bridges, dialplan, the PJSIP objects, AMI, ARI and AGI, realtime config, versions and end-of-life dates.
Asterisk · 25 min read
An Asterisk auto attendant, built line by line.
A complete bilingual business auto attendant in the Asterisk dialplan: menus, retries, hours and holidays, ring groups, mobile screening and voicemail by email.
Asterisk · 28 min read
Running Asterisk in production: toll fraud, hardening and upgrades.
How toll fraud hits internet-facing Asterisk and how to stop it: PJSIP ACLs, dialplan limits, fail2ban, TLS/SRTP, NAT, CDR/CEL, patching and LTS upgrades.

Where Asterisk fits

Asterisk is a back-to-back user agent and media server: it terminates calls, plays prompts, records voicemail and bridges channels. It is not a SIP proxy built to route millions of registrations; that is the job of Kamailio and OpenSIPS, covered in open-source VoIP. Many production systems use both: a proxy at the edge and Asterisk behind it.

Articles on this topic

Topics Auto attendant VoIP Call routing All topics

Article · 22 min read
Call Queue vs Ring Group vs Auto Attendant: Guide
A 2026 guide to call queues, ring groups, hunt groups, and auto attendants, with an all-busy test, peak-overlap worksheet, platform limits, and small-team routing scenarios.
Article · 26 min read
How to Get a Business Phone Number: Options & Costs
Learn how to get a business phone number in 2026, compare eight option types and real team pricing, and check porting, identity, toll-free and emergency-calling requirements.
Article · 22 min read
Business Phone Time Zone Settings: A Routing Test
A 2026 guide to business phone time zone settings, with a clock register, holiday and after-hours conflict tests, dated DST conversions, and a provider scheduling decision card.
Article · 22 min read
How Many Phone Lines Does Your Small Business Need?
A 2026 worksheet for sizing business phone capacity using public numbers, users, devices, peak concurrent calls, vendor questions and acceptance tests.

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