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Linux PBX Part 2
If you have ever wanted the features of a PBX for a small business, or at home, but couldn't justify the expense, the open sourced Asterisk software may be the ticket for you. The second part of this series introduces hardware alternatives.
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By
Henry
Davis
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Audio DesignLine
(08/18/2006 10:15 AM EDT)
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Asterisk operates under the Linux or other Unix-based operating system mentioned in part I. While Asterisk will run on many different systems including low end consumer PCs, the primary limitations will be determined by what type of interface cards used to connect to phone lines and phones. A partial list of interface hardware known to work with Asterisk is included below.
Many telco interface boards use the PCI interface. When choosing a PC to host these boards you need to carefully check what the requirements are for any PCI card you select in terms of PCI slot type: 5 volt vs. 3.3V, 32 bit vs. 64 bit, 33 Mhz or higher. The X100P clone cards require 5 volts and won't work in motherboards that can't supply 5 volts. The cards should be keyed so they will only fit in 5V slots, but some of the clone cards have the notch in the PCI connector that will allow them to fit into 3.3V slots. When a 5V card is accidentally placed into a 3.3V slot the system won't power up.
The DIGIUM TE410 PRI card, requires a motherboard with a 64bit 3.3v PCI slot. Given the bandwidth requirements, it would be better to have a 133Mhz slot if available.
The DIGIUM TE405P PRI card uses the more commonly available 32bit 5 volt PCI slot, so you have a wider selection of motherboards for this card. Other than the PCI slot type, this board is virtually identical to the TE410P.
Some cards like the TDM400's are 3.3V cards, but to make up for their higher power requirements, they require an available hard drive power connector in order to get 5V or 12V.
Ideally you will choose a motherboard that allows BIOS specification of the IRQ to a PCI slot to avoid IRQ conflicts.
Linux commands aid in the diagnostic process: you can use the command "cat /proc/interrupts" to see the interrupt allocations and possible conflicts.
The command "lspci -bv" also provides additional information regarding IRQs.
Apart from paying attention to basic hardware compatibility, the usual admonition when buying a generic PC for which you are not sure of the software performance requirements applies. Buy more than you think you need because you'll find more bells and whistles that take CPU cycles.
Asterisk enjoys a large user community that is helpful when configuration questions arise. Or, if you want professional assistance and have the cash, Digium offers professional alternatives that include regression testing and professional configuration assistance. Developing a home "PBX" is entirely possible using any one of a number of analog phone line interface cards, while full blown enterprise capability is available through T1 interface cards. Features are selectable during system configuration.
Asterisk is just one of the many open source software initiatives available to solve a wide variety of problems. The Asterisk software provides full featured PBX services while allowing you to select from a range of support options. When looking for a solution to a problem that you might solve through purchase of a complete turn key package it's always valuable to spend a little time looking for an open soure alternative. It may solve your problem, but it t least provides you with more knowledge when shopping for a pre-packaged solution.
Atcom
AX-100P: one fxo pci card, compatible digium x100p
AX-4E: Same as Tormenta2 and Digium's E400P cards
AX-4T: Same as Tormenta2 and Digium's E400P cards
BroadTel:
BroadTel TDM001 X100P Clone PCI card
BroadTel TDM004 TDM400 Clone PCI card
Digium:
Wildcard TDM400P 4 Port Analog Card
Wildcard TDM2400P 24 Port Analog Card
Wildcard TE411P 4 Port T1/E1/J1 Card with Hardware Echo Cancellation
Wildcard TE410P 4 Port T1/E1/J1 Card
Wildcard TE406P 4 Port T1/E1/J1 Card with Hardware Echo Cancellation
Wildcard TE405P 4 Port T1/E1/J1 Card
Wildcard TE210P 2 Port T1/E1/J1 Card
Wildcard TE205P 2 Port T1/E1/J1 Card
Wildcard TE110P 1 Port T1/E1/J1 Card
Digivoice - Brazil:
VB0408 FXO 4/8 Analog Ports - With built in GSM codec, Echo Cancelation and pulse detection into DSP
VBE16060 1/2 E1 Ports - With built in GSM codec, Echo Cancelation and R2D/MFC protocol into DSP
Eicon
Diva Server V-Series provides a dedicated range of telephony adapters that provide rich media processing capabilities for enabling voice, speech and conferencing applications.
Diva Server V-PRI - Connects to 1 E1/T1 Line
Diva Server V-2PRI - Connects to 2 E1/T1 lines
Diva Server V-4PRI - Connects to 4 E1/T1 lines
Diva Server V-Analog - Connects to either 4 or 8 Analog lines
Diva Server PRI/E1/T1-CTI -Connects to a E1 or T1 line
Diva Server PRI E1-30 -Connects to an E1 Line
Diva Server PRI T1-24 -Connects to a T1 Line
Openvox
A400P PCI Card - TDM400 clone
A100P PCI Card - X100P clone
Parabel cards:
Quasar E1 Original E1 cards with 2/4/8 E1 interfaces, DMA controller and opensource driver.
Quasar-2PCI/PMC
Quasar-4PCI/PMC
Quasar-8PCI/PMC
PBX Hardware - Affordable Quad/Double/Single T1 and E1 cards http://pbxhardware.com
T200P Double T1
E200P Double E1
T400P Quad T1
E400P Quad E1
TE400P Quad T1/E1
QuadBRI 4 Port ISDN BRI active Card
REDFONE Communications Quad T1/E1 to Ethernet bridge.
Solid-state appliance designed for deploying high-availability, redundant Asterisk clusters.
Sangoma cards
A101 One port T1/E1 card
A102 Two port T1/E1 card
A104 Four port T1/E1 card
A104d four port T1/E1 PCIx card with 128ms telco grade hardware echo canceller
A108 Eight Port T1/E1 card
A108d Eight Port T1/E1 card with 128ms telco grade hardware echo canceller
A200 expandable 2 to 24 analog ports of FXO and or FXS
A200d expandable 2 to 24 analog ports of FXO and or FXS with 128ms telco grade hardware echo canceller
Varion Zapata Telephony T1 and E1 cards: http://www.govarion.com
Voicetronix cards
OpenPCI-4 & OpenPCI-8 4 and 8 FXO/FXS PCI cards
OpenSwitch6 & OpenSwitch12 6 and 12 FXO/FXS PCI cards
OpenLine4 4 FXO PCI card
OpenPRI Single and dual E1/T1/J1 PCI cards
Xorcom - Asterisk Channel Banks and iPBXs
Astribank-8 - The first channel bank designed for Asterisk - 8 FXS ports.
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