How to Build an Embedded Asterisk IP-PBX rowetel.com/ucasterisk

Contents Free Telephony Project Why Embedded Asterisk Motivation Open Hardware Open Hardware Hacking Credits Products Demo

Free Telephony Project 1 many people working in open software we are working in open hardware professional telephony hardware designs that we give away to improve the world a little

Free Telephony Project 2 designs can be copied modified, re-used without restriction we encourage cloning of our products trend: functionality shifting from hardware to (free) software trend: total system costs constantly dropping

Free Telephony Project 3 falling hardware costs are a good thing (especially for the developing world) so rather than protecting IP we leverage these trends by giving away free hardware designs and encouraging cloning!

Why Free Telephony Project? Hardware designs are free as in speech Use FOSS and Open Hardware to drive system costs to $0 Lower the cost of telephony for everyone on the planet A phone call should be a human right, not a privilege

Why Embedded Asterisk Small size (DSL router) Low power 3W (battery, solar)! No moving parts (fans or disks) Quiet Reliability (parts count, connectors) Low cost (few hundred $) Just plain cool!

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 sponsor 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!

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

Motivation 1 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 2 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 1 reference designs that anyone is free to copy, re-use, modify CAD files, prototypes differences from open software atoms cost more than bits you need a factory

Open Hardware 2 many advantages over closed development similar to open software many eyes low bug count dramatic reduction in R&D cost and time

Open Hardware 3 normal hardware costs include 70% overhead exciting new business models, e.g. OLPC dramatic price reductions local manufacture customisation, localisation, e.g. solar, wireless

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

Credits In no particular order: Atcom (China) for putting the IP04 into mass production Astfin team for developing build system, PRI and BRI-ISDN hardware Analog Devices for Blackfin and great uClinux support Linux and Asterisk communities Many others who contributed (e.g. drivers, software fixes)

Open Hardware IP-PBX Products IP04 4-port Analog IP-PBX (production) IP08 8-port Analog IP-PBX (prototype) E1/T1 PRI-Appliance (prototype) BRI-Appliance (prototype)

Case Study - IP04 Switches analog and VoIP calls fanless, low power (5W), rugged, compact open hardware and software easy to customise, e.g. simple UI potential for very low cost ($100), compared to $2,000 retail for similar products stable but not feature complete (CID, GUI)

Case Study – IP04

PRI Appliance (Astfin Team)

BRI Appliance (Astfin team)

Demo Boot from a Battery Make a phone call telnet in GUI NAND flash

Questions? For more information rowetel.com/ucasterisk

Notes demo? Maybe ask Mike, Idea: battery powered, or photo of Alberto's miniPC to compare. New GUI? Hook up battery in front of them and boot? Telnet in? intro some sticky new ideas and geeky experiences