Dropbear Consulting

Asterisk

Asterisk is an open source, software PABX than competes well with more expensive traditional PABXs.

This table compares an Asterisk PABX with a traditional or 'IP enabled' PABX:

Attribute	Asterisk	Traditional
Hardware	Standard Linux server hardware plus interface cards.	Proprietary. IP support may require special LAN hardware or reconfiguration.
Expandability	Standard server hardware and standard phones makes expansion easy. SIP protocol means no server changes for new extensions.	Limited by cards/chassis capacity for fixed lines. IP versions may support SIP or similar protocols for network extensions.
Location Transparency	Moving a SIP soft or hard phone only requires a network port and the phone will work at any location.	Moving a fixed line phone requires at least re-patching. IP versions generally have the same location transparency as Asterisk.
Handsets	Many different SIP (standard) IP phones, soft phones, analogue devices if required.	Proprietary handsets or analogue handsets.
Features	Many, many features included with standard package or available as free downloads from the developer community.	Depends what you paid for. Useful things like voicemail often incur extra costs.

So why would you install Asterisk?

This real-life case study shows how a small organisation implemented Asterisk to save costs and improve functions.

A small consulting company has a main office with a secondary site in the same city. Two consultants also work from home sometimes.

In the main office the current phone system is an old key system (Commander style) with three analogue lines
Main office fax and modem lines are separate.
In the secondary office there is a single phone line with separate fax and modem lines.
Home workers have no visibility to the office PABX.
No voicemail or conferencing facilities available.

Many of the analogue lines are relatively unused, incurring costs for no advantage.

The lack of features such as conferencing is causing difficulties - alternative conferencing arrangement have proven inadequate.

Consultants cannot effectively work from home - data connectivity is available through VPN facilities but telephony is unavailable.

Replace the current key system with an Asterisk PABX. Eliminate the analogue services (other than the modem line) at the secondary office.

Introduce VoIP service provider for long distance calls.

Provide soft phones for working from home.

Dropbear Consulting has experience in planning, installing, configuring and supporting Asterisk PABX systems.

You might want to examine the white paper Planning for Asterisk available from the resources page.

History doesn't repeat itself, but it does rhyme. – Mark Twain