User:Heath/PBX
This is probably the only area that I can call myself an expert in.
Asterisk can be made to build a tricked out phone system of any size at a trivial cost.
Ultimately, this page will be a set of config files, patches and dependencies for building such a system.
Current version doesn't do GSM. Mainly because I have no idea how to do it.
Contents
Compression
- MELP/MELPe - Military grade compression for minimizing bandwidth consumption
- AMR - What cellphones use
- g723.1/g729 - What voip phones use
- iLBC/speex - Open source low-bitrate codecs
Useful protocols
- Bluetooth will be implemented via chan_bluetooth or chan_cellphone
- GSM will be implemented with a commercial gateway.
- Regular POTS service can be done using hardware
- SIP - VoIP protocol
- IAX2 - Lightweight VoIP protocol
Equipment/Costs
- At least a P4 2.4 2GB server with a focus on reliability (solid disk, passive cooling if possible) $1000
- Backup server/load balancer $1000
- Half decent switch $300
- Digium AEX2460E Analog Card 6x4 FXS + Echo can $1800
- g729 licenses $100
- 20U Rack $500
- Rackmount UPS $500
- Two serial MELPe hardware modules $1000 (This could be way off)
- Far end server colocation $400/month
- Total: $6200
- Recurring: $400 per month plus cost of minutes
- Doesn't include wiring because that depends entirely on the layout of the structure.
Dependencies
- Existing network/Internet
- Cool/dry/secure area
- ~1000 watts available power
Asterisk
- Used to switch calls
- Used to translate between various protocols
- Used to perform IVR functionality such as voicemail
Security
- IAX2 has an aes128 option
- Bluetooth (cough) security
- Not all that great in the open source world, but reasonable security can be achieved.
Instructions
- Build servers. Insert Digium card/s.
- Load the ups/servers/patch panels into the rack.
- Connect power; connect servers to switch
- Load Debian or Ubuntu Server onto the servers.
- Follow these instructions - Easy if you've done it a few times.
- Follow these instructions - Have a friend nearby to take your aggression out on.
- Install my MELPe hacks.
- Install your favorite billing software
- Connect the system to the LAN/WAN
- Order a dedicated server, nothing special.
- Install Debian, then Asterisk, like we did before
- Have colo personnel install MELPe hardware, then install MELPe hacks
- Follow these instructions to connect to the colo server
- Subscribe to server per minute voip providers and configure them on the dedicated server
- Connect to them via _X.,1,Dial(sip/myprovider/${EXTEN})
Using a colo is avoidable if enough bandwidth is available. Will TSI one day be the termination point for HF?
