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VoIP PBX Interface Selection Guide (Asterisk Hardware)
Because voice over IP is digital, often a standard PC or server is used for the PBX.
Those VoIP PBX's (aka IP PBX) need PCI interface cards to connect to analog telephone lines, digital T1/E1 lines, analog telephone handsets and fax machines.
This category contains PCI interface cards from the leading manufacturers in the industry. If you are using Asterisk IP PBX or a variant such as
trixbox, Elastix, AsteriskNOW, FreePBX and need to connect it to something, we are here to help. For our complete
IP PBX Interface Buying
Guide please browse to the bottom of this page.
Sangoma,
Digium,
Rhino,
OpenVox,
Redfone,
Xorcom,
Dialogic
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Telephone Circuit Interface Buying Guide
Telephone
circuit interface cards are used to connect regular PC's and servers to
analog and VoIP (digital) telecommunication equipment. Typically, this
is done by inserting a PCI card (while the system is turned off) into a
computer and installing any required drivers or software. The
installation and configuration of these PCI cards should be performed
by an experienced technician. Voiplink has sold thousands of PCI cards
over the years, and our expereinced technical sales staff can assist
you should you have questions.
To determine what specific PCI card you need, you need to know three things about your existing equipment. First, you need to know what types
of circuits you are connecting to. You will also need to decide if you need to have hardware echo cancellation on the card. You will also need to know
what PCI interface slots you have available on the motherboard of your computer. This will determine what type of interface you will need on the card.
1) What are you connecting to:
How many analog telephone lines do you have?
- This is how many FXO ports you need
How many analog telephones & fax machines do you have?
- This is how many FXS ports you need
How many T1/E1 circuits do you have?
- This is how many T1/E1 ports you need
Remember to plan for growth!
2) Do you need echo cancellation:
If
this is your first time installing a PCI card on the line it will be
hard to predict whether or not you will experience echo. There are
software tuning techniques to remove echo from the line but they
consume system resources and are often inadequate.
Some manufacturers like Digium allow you to add the echo cancellation module to the card after you purchase it. This is beneficial because you can save some money up front (no hardware echo cancellation module) and upgrade later if you find you have echo on the line. Cards from most other manufacturers either include hardware echo cancellation or they do not, and it cannot be added later. I always use and recommend hardware echo cancellation, it's just one less thing to worry
about. If I'm installing a system for a client, its not worth the damage to our reputation or the truck roll if echo pops up.
3) What type of motherboard interface do you need:
Next you need to determine what type of PCI interface your computer has
available. At the time of writing, Voiplink sells 3 types of interfaces:
-
Standard PCI (older but, most common)
- PCI Express (newer, faster, but less common)
- MiniPCI (newest, specialized, but less common)
time of writing Dec '08
Standard PCI has been around forever and it's in almost every
motherboard today. It is usually slightly cheaper than PCI Express
(although Sangoma leveled their prices in late '08). I recommend
Standard PCI because it's usually cheaper and people will most likely
have this interface in their computer. That being said, eventually PCI
Express will replace Standard PCI and the tables will be turned. PCI
Express is faster and some people claim that VoIP benefits from the
speed increase. I am a bit skeptical but I have never seen any evidence
either proving or discounting this claim.
MiniPCI is a bit of a new comer to the VoIP industry. OpenVox released
their A400M series MiniPCI cards earlier this year. The interface is
found on small form factor systems and solid state appliances. MiniPCI is excellent for small, low power that just need basic features.
Finally, I will discuss the various PCI card manufacturers that we offer.
Sangoma Technologies
Sangoma
interface cards allow you to connect voice over IP PBX's to
T1/E1services, analog telephone lines, analog telephones and fax
machines. Sangoma offers optional hardware echo cancellation on most of
their cards and they are available in Standard PCI and PCI Express. Sangoma is well known for their innovative AFT architecture that requires only a single PCI or PCI Express slot yet can scale to 24 ports. Sharing the PCI interface ensures common synchronous clocking for all channels. Sangoma's compact form factor can fit large port densities in almost any standard sized ATX case, something their competition can have a problem doing. Sangoma's A series card carry the industry's first and only Lifetime Manufacturer Warranty.*
*To qualify for Lifetime Warranty protection, the product must have been purchased from an Empowered by Sangoma partner, and the product must be registered by the end user at http://sangoma.com/warranty/register/
Voiplink is an Empowered by Sangoma partner.
Digium
The
creator and primary developer of Asterisk IP PBX software, Digium
offers a complete line of interface cards to connect your IP PBX's to
T1/E1services, analog telephone lines, analog telephones and fax
machines. Optional hardware echo cancellation is available on most of
their cards. Digium offers both Standard PCI, & PCI Express
interfaces. Digium solutions reduce the costs of traditional TDM and VoIP implementations through Open Source, standards-based software and next-generation gateways, media servers, and application servers. Digium was founded in 1999 by Mark Spencer whose mission is
to transform the way businesses acquire and operate their
communications systems through the application of open source software.
Rhino Equipment
Rhino's high quality - made in America interface
cards allow you to connect your IP PBX to T1/E1 services, analog
telephone lines, analog telephones and fax machines Optional hardware
echo cancellation is available of many of their cards. Rhino offers PCI
cards in both Standard PCI and PCI Express. They also offer a popular
line of channel banks to provide FXS/FXO, T1/E1 connectivity.
Openvox
Has a wide selection of budget-conscious
interface cards with FXS/FXO ports and T1 / E1 ports for most IP PBX's.
Connect your IP PBX to analog telephones, fax machines and analog
telephone lines. A few of Openvox's cards have hardware echo
cancellation and they offer Standard PCI, PCI Express & MiniPCI
motherboard interfaces.
RedFone
Manufacturers a line
of T1/E1 hardware that is designed to provide immediate failover
capabilities. The RedFone devices can detect a failure of the digital
circuit and reroute calls to another circuit almost instantaneously.
Xorcom
Unique USB-based channel banks offer an affordable and flexible
solution for expanding an IP PBX system with more FXO or FXS ports.
While unconventional, the Xorcom Astribank products are ideal for high
density analog ports and have the advantage of being able to work with
even the smallest appliance systems so long as there is an available
USB port.
Common Terms:
Asterisk is the most popular open source IP PBX in the world. Many
variations of Asterisk are now available such as trixbox, AsteriskNOW, and
elastix that can provide advantages and disadvantages over the original
Asterisk. These IP PBX's can be loaded on to personal computers or business
servers to build a feature rich, business grade voice over IP phone system.
There
are four main types of interfaces on an IP PBX, FXS, FXO, T1/E1 and
Ethernet. An FXS interface is used to connect analog telephones or
faxes to the IP PBX.
An FXO interface is used to connect analog telephone lines to the IP
PBX. A T1/E1 interface is used to connect
the IP PBX to high speed, ultra-reliable internet connections. Ethernet
interfaces are used to connect an IP PBX to the local area network
(LAN).
T1/E1
Highly
reliable digital data connection. Some VoIP providers can install a
T1/E1 circuit to deliver phone calls to your IP PBX system. T1 is the
US standard and E1 is the European standard. If you have a VoIP
connection delivered over a T1, you do not need any telephone circuit
interface equipment.
PRI (Primary Rate Interface)
A PRI is a telephony circuit that is delivered over a T1/E1 circuit, this is the industry standard for delivering voice phone calls to business customers.
Over a T1 you will get 24 simultaneous calls and an E1 will get you 30
simultaneous calls. You will need a T1/E1 interface card to use these
types of circuits.
FXO: Analog telephone line connection (POTS) -
1 call per port - An FXO connection connects to an analog telephone line jack.
FXS: Analog telephone or fax machine
connection - 1 device per port
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