How to Build an Embedded Asterisk IP-PBX

Topics IP-PBX and Asterisk Why Embedded? IP PBX Hardware 101 Free Telephony Project and Open Hardware Status The Future Opportunities

IP-PBX and Asterisk A open source PABX (PBX) that can route calls between the PSTN and VOIP Usual FOSS advantages – low cost and open VOIP experiencing massive growth Primary sponser Digium but many contributors Hence alternatives such as FreeSwitch, CallWeaver, etc, etc

Introduction Typical installation x86 PC plus PCI card to connect to the telephone lines/telephones. Paradigm shift away from x86/PCI cards History: Embedded = IP-only and no DSP (Echo cancellation and codecs not possible) Analog Devices Blackfin Processor has challenged this paradigm!

Why Embedded Small size (DSL router) Low power < 5W (battery, solar)! No moving parts (fans or disks) Quiet Reliability (parts count, connectors) Low cost (a few hundred $ street) Just plain cool!

Blackfin Processor A powerful DSP (1 GMAC) AND runs uClinux Breaks the two processor (host/DSP) paradigm Low cost ($5 - $15 each) Well supported by vendor and community Open hardware and software

IP-PBX Hardware 101 PCI Bridge FXO Port x86 CPU DSP hardware Asterisk Ethernet Card FXS Port Host PCPCI Card Device Driver

IP-PBX Hardware 101 FXO Port Blackfin CPU DSP software Asterisk Device Driver FXS Port Embedded PBX

IP-PBX Hardware 101 Many redundant parts removed  Lower cost  Smaller size  Lower power  Enhanced reliability Don’t need “hardware” DSP – Blackfin CPU is a DSP

Challenges Complex development environment –Cross compiler & tool-chain –Customized kernel and apps Learning Curve Low memory ~64MB uClinux (offset by partial MMU) Care and feeding of the cache

Who is working on Blackfin Asterisk? Several individuals and companies working on Blackfin Telephony products. Expect to see many embedded Telephony products in the near future This presentation focuses on the activities of the Free Telephony Project

Free Telephony Project Goals Build a completely open embedded telephony platform. Hardware designs are open. Full design and manufacture information available for download.  Schematics, PCB layouts, HDL code, unit tests

Motivation Various motivations across the people and companies involved in the project. Obvious business potential in a $200 IP- PBX with multiple ports. Enabler for service models. My motivation is Social & Geeky rather than Business.

Motivation I like building stuff Would like to use my hardware/DSP skills to improve the world a little Open software like Linux and Asterisk has been a great thing for the World. Craig Newmark (Craigslist) : Nerd values “Get yourself comfortable, then do something fun to change the world a little”

Open Hardware The designs are free as in speech A community exists that are sharing designs and helping each other. Build better hardware faster using open development models. Opportunities for small business. It’s working!

Hardware Projects (so far) BlackfinOne DSP Motherboard (mature) 4-8 port FXO/FXS Analog (mature) E1/T1(prototype hardware and driver) BRI-ISDN (stalled) IP04 $100 IP-PBX (mature)

How to Hack Telephony Hardware in Linux Schematic Entry (gschem) PCB Design (PCB) Verilog HDL (Icarus)

Port Asterisk to Blackfin (gcc) Design Schematics (gschem) Design PCBs (PCB) Assemble Prototype Hardware Debug and Test Hardware Write Verilog Code (Icarus) Integrate and Test system Design Process Flow

gschem Schematic Entry

Analog Hardware Example

Hardware Hacking is Getting Easier!! Build sophisticated surface mount circuits. Order strange parts on-line e.g. Digikey Prototype PCB costs dropping Stereo Microscope + soldering tools < $500 Open hardware designs Free CAD tools Help from on-line communities

Status Port Asterisk to Blackfin Develop DSP Motherboard Develop Analog Hardware Production Engineering Volume Manufacture IP04 Prototypes Port driver to Blackfin Sep 2005 Sep 2006Jan 2007 May 2007 Q3 2007

Performance 500 MIPs Available (1 GMACs)  G729A (8 MIPs)  Speex (15-30 MIPs) Simultaneous SIP Calls (approx 50) Echo Can  Depends on tail  ports depending on tail

Opportunities Business Individuals End Users

Opportunities for Business Massive Differentiation Cost/Margin advantages New products we haven’t even thought of:  Asterisk ATA or fax  Asterisk in an very smart IP-phone  T1 IP-PBX in an ATA form factor for $200  ?

Opportunities for Individuals It’s open. All of it. Hardware and software. Even the CAD tools! Exciting project in early stages Chance to really contribute It’s very different from x86/PCI Helped needed: Hardware, software, Asterisk config

Opportunities for End Users Lower end user cost – a $300 (street) 4-port IP-PBX in 2008? IP-PBX functionality in the home rather than current ATA. Bring telephony to developing countries. Small, fan-less lets you reach markets like SOHO that don’t want a PC for their phone system.

Getting Started Buy a Blackfin STAMP Card ($226) Buy a 2 FXO 2 FXS port Analog Starter Kit ($299) Start Hacking

Questions? For more information geda.seul.org blackfin.uclinux.org