Multitech VoIP User manual

telephony internet access remote access modems

Content
Toll-bypass Long Distance Calling ...................... 1
What Is VOIP? ......................................................... 2
That Was Then...
This is Now...
Immediate Cost Savings ....................................... 3
Applications ........................................................... 3
Office-to-office Communication
Off-net Calling
Create Off-premise Extensions
Replace Expensive Tie Lines
Business Quality Voice .......................................... 4
Bandwidth Requirements .................................... 5
Interoperability ...................................................... 5
VOIP Solutions ........................................................ 5
Routers
VOIP Server Cards
IP-based PBX
PC-based Telephony
IP Gateways
The Multi-Tech VOIP Solution.............................. 7
Easy to Install
Low-risk
Scalable
Easy to Use
Requirements
Models
Try VOIP Now! ......................................................... 8
VOIP Terms .............................................................. 9

1
Toll-bypass Long Distance Calling
Now multi-location businesses can use the Internet or a
private network (Intranet) for long distance voice and fax
communications and save thousands of dollars annually.
Instead of paying your long distance
carrier to route long distance
calls between offices, any IP
data network can route the
calls using a technology
called Voice over IP
(VOIP). It doesn't
matter if you are
using the Internet, a
private Intranet,
ISDN, DSL, frame
relay, wireless, or
satellite for your data
communications
network, as long as it
uses the Internet Protocol
(IP).
If you make frequent long distance calls to a remote site,
you already know the charges can add up quickly.Voice
over IP is designed to help you maximize the investments
you’ve already made in your data and telecommunications
network infrastructure by bridging them together to
provide toll-free communications.
This guide provides telecommunication managers and
data communications managers with an introduction to
Voice over IP and how they may benefit from voice and
data convergence.

What is VOIP?
VOIP lets you make toll-free long distance voice and fax
calls over existing IP data networks instead of the public
switched telephone network (PSTN).Today businesses that
implement their own VOIP solution can dramatically cut
long distance costs between two or more locations.
That Was Then...
For the past 100 years people have relied on the PSTN for
voice communication. During a call between two
locations, the line is dedicated to the two parties that are
using it. No other information can travel over the line,
although there is often plenty of bandwidth available.
Later, as data communications emerged, companies paid
for separate data lines so their computers could share
information, while voice and fax communications were
still handled by the PSTN.
This Is Now...
Today, with the rapid adoption of IP, we now have a far
reaching, low-cost transport mechanism that can support
both voice and data. A VOIP solution integrates seamlessly
into the data network and operates alongside existing
PBXs, or other phone equipment, to simply extend voice
capabilities to remote locations. The voice traffic
essentially“rides for free” on top of the data network using
the IP infrastructure and hardware already in place.
2

3
Immediate Cost Savings
VOIP solutions provide the potential to save substantial
amounts in long distance charges. Businesses with remote
offices worldwide or just in a different area code miles
away can profit from a VOIP solution. Even with the most
inexpensive calling plans, a VOIP network, such as
Multi-Tech’s MultiVOIP gateway solution, can quickly
return your investment and begin paying you back.
In fact, after the one-time investment is paid off, the
VOIP solution begins to create profit for your company.
Applications
Voice over IP is ideal for multi-location businesses looking
to reduce toll charges associated with intra-office calling.
It is designed to help you maximize investments you’ve
already made in your data and voice network
infrastructure. Some examples of the many applications
for a voice over IP network include the following:
Office-to-office Communication
A VOIP network can be as small as two offices or as large
as hundreds of offices. Each office installs and configures
a VOIP solution on their network to begin placing calls or
sending faxes to the other offices on the VOIP network.
Off-net Calling
Telecommuters or customers off the IP network can make
toll-free long distance calls by dialing into a local VOIP
solution and placing calls to any other location on the
VOIP network.You can even have a VOIP solution at a
remote site dial a local phone number for a free person-
to-person long distance call.
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4
Create Off-premise Extensions
Extend the reach of your PBX into home office locations.
Simply connect a VOIP solution to the PBX at the
corporate office, and another VOIP solution at the remote
office. Now, anyone can place calls to the remote office
by simply dialing an extension number.
Replace Expensive Tie Lines
A company that utilizes tie lines to connect branch office
PBXs to the corporate PBX can now use their own IP-based
Wide Area Network to complete the call.
Business Quality Voice
Independent tests of VOIP systems have shown that they
are perfectly capable of delivering“toll-quality”voice.The
actual voice quality your business will experience,
however, is affected by a number of factors: WAN
bandwidth (the higher the better), voice compression and
network conditions such as latency (average“travel”time
it takes for a packet to pass through the network). On a
private Intranet you can control all of these factors to
achieve near toll-quality voice connections. When using
the public Internet, you can control everything but the
latency factor. Latency, however, can be managed to
enhance your voice quality with a quality of service
guarantee from your ISP.
When network traffic is at peak levels, voice can be given
priority over data to ensure
consistently high voice
quality using the
Differentiated Services
(DiffServ) Quality of Service
(QoS) protocol. Other
features such as forward
error correction, bad frame
interpolation and dynamic
jitter buffers, can further
enhance voice quality.
“We made hundreds of
test calls using the
(MultiVOIP’s) outside
lines, and most people
we called couldn’t tell
that we weren’t on a
standard long distance
line.”
—PC MagazineTest Center
February 9, 1999

5
Bandwidth Requirements
One common misconception about VOIP is that it is a
bandwidth hog, when, in fact, voice is a very efficient type
of traffic.Voice compression standards like G.729 (8:1)
and G.723 (10:1) are used to minimize the bandwidth
required for voice. G.723, for instance, is the maximum
compression rate and requires only 5.3K bps (plus an
added 7-8K bps for IP overhead). Even at maximum
compression, your VOIP solution will still provide near
toll-quality voice.
As a rule of thumb, 14K bps of bandwidth per call is ideal.
This includes the compressed voice packet and the IP
overhead.To determine total VOIP bandwidth needed per
location, take the number of VOIP channels being used
and multiply by 14K bps. Then double this number to
accommodate for both voice and data traffic.
It should also be noted that bandwidth is used only when
someone is speaking.A silence suppression/Voice
Activation Detection (VAD) feature is an option that frees
unused call bandwidth for data traffic. This is significant,
since callers are usually silent for 60 percent of the call.
Interoperability
Standards are still emerging that ensure VOIP features
work with different vendor solutions. The H.323 standard
is the one most widely deployed and is the only approved
protocol adopted by the International Telecommunications
Union (ITU). The H.323 standard provides support for
audio calls to other H.323 clients, gateways, gatekeepers
and conference servers. Another emerging standard is the
Session Initiation Protocol, or SIP. Look for products that
are adopting these two standards.
VOIP Solutions
From the wide variety of VOIP solutions available today, the
one you select depends on the size of your business, the level
of networking expertise available, the amount of
integration with legacy equipment, and the level of voice
quality you require.
Routers
Router solutions usually replace an existing network
router and keep voice and data all in a single box.
However, this solution requires networking expertise, and
can be costly to install, while placing network services at
risk during deployment and maintenance.

VOIP Server Cards
VOIP server cards can be an economical VOIP solution.
However, they must be compatible with the server and
operating system and installations can be complex.
IP-based PBX
The IP-based PBX is usually software running on a
computer based server. However, it often requires a
forklift upgrade of the existing
PBX, or at a minimum, an
extensive software and/or
hardware upgrade. An IP-based
PBX is typically marketed to
new installations where no
legacy system is in place.
PC-based Telephony
PC-based telephony software is by far the cheapest VOIP
solution, but it is also the clumsiest. It requires users to
make phone calls using their PC instead of a phone. This
usually involves user training and an investment in
speakers and microphones for each PC. Plus,many users
complain that voice quality for this solution is not
adequate for business communications.
IP Gateways
An IP gateway, like Multi-Tech's MultiVOIP, is often the
most suitable VOIP solution for small to midsize
businesses and remote sites. It does not disturb your
existing data infrastructure because it simply drops into
the Ethernet network. Furthermore, it operates alongside
existing PBXs or other phone equipment to extend voice
capabilities to remote locations or users. An IP gateway
requires only a minimal investment in product,
installation, and user training.
6
Planning a VOIP Implementation
• Encourage data communications managers and
telecommunications managers to work together.
• Choose a solution compatible with existing and planned
systems.
• Ensure that the VOIP product utilizes industry standards
(ITU G.711, G.729, G.723, H.323, SIP, etc.).
• Manage your bandwidth by giving priority to real-time
traffic, like voice and video.
• Keep VOIP calling as easy and seamless as possible by
selecting a product that has calling procedures
similar to your existing phones.

The Multi-Tech VOIP Solution
Multi-Tech's award-winning
MultiVOIP provides an
easy and low-risk way
for your business to
save on long distance
voice and fax costs.
Easy to Install
You don't have to change your PBX, data network, or
Internet/Intranet access to implement the MultiVOIP
solution. There is no
integrating this device
with a PC, a server, or
operating system. And
to simplify installation,
the central site can
preconfigure all units
before sending them to
the remote sites.
Low-risk
MultiVOIP allows you to implement VOIP without
interfering with your network infrastructure or phone
system. If there are problems with the VOIP installation or
the IP network goes down, you can still pick up your phone
and use the PSTN to place a long distance call.
Scalable
The MultiVOIP design allows you to expand VOIP support
as needed. Add more VOIP ports at a busy site with
another MultiVOIP.Add another office to your VOIP
network by installing a MultiVOIP at that office.
Easy to Use
Placing calls with MultiVOIP is like using your existing
phone system. No end-user training is required.
7
MultiVOIP:
• eliminates toll charges
between offices
• requires no changes to
phone or network
systems
• installs in minutes
• easy to use

Requirements
You probably already have what you need to deploy a
MultiVOIP network and start saving on long distance calls.
To determine the number of ports that you need, first
determine what percentage of the long distance bill is used
for intra-office communication (typically between 25-
40%), then multiply the percentage by the number of lines
at the location. If you are using tie lines, for every line
that you support, you will need one port on the MultiVOIP.
MultiVOIP Models
To learn more about the MultiVOIP family visit our web
site at www.multitech.com/products/multivoip.
Try VOIP Now!
You be the judge! Call our toll-free demo (in the USA)
1-877-TRYVOIP and hear for yourself how clear
the connection can be.
8
MultiVOIP Site Requirements
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Ethernet LAN
❏ IP network
❏ IP addresses
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VOIP Terms
bad frame interpolation interpolates lost/corrupted
packets by using the previously received voice frames. It
increases voice quality by making the voice transmission
more robust in bursty error environments.
compression is used at anywhere from 1:1 to 12:1 ratios
in VOIP applications to consume less bandwidth and
leave more for data or other voice/fax communications.
The voice quality may decrease with increased
compression ratios.
DiffServ (Differentiated Services) is a quality of service
protocol that prioritizes IP voice and data traffic to help
preserve voice quality even when network traffic is heavy.
dynamic jitter buffer collects voice packets, stores them,
and shifts them to the voice processor in evenly spaced
intervals to reduce any distortion in the sound.
E&M (Ear and Mouth) is the interface on a VOIP device
that allows it to be connected to analog PBX trunk ports
(tie lines).
forward error correction increases voice quality by
recovering lost or corrupted packets.
FXO (foreign exchange office) is the interface on a VOIP
device for connecting to an analog PBX extension.
FXS (foreign exchange station) is the interface on a VOIP
device for connecting directly to phones, faxes, and CO
ports on PBXs or key telephone systems.
H.323 is an industry-standard call setup protocol
designed to standardize VOIP communications between
other H.323 telephony solutions.
ITU G.723, G.726/G.729 and G.711 are some of the
standards developed for compression technologies.
latency is the average “travel”time it takes for a packet
to pass through a network.The lower the latency, the
better the voice quality.
PSTN is the public switched telephone network that
traditionally routes voice calls from one location to
another.
SIP (Session Initiation Protocol) is a signaling protocol
for Internet conferencing, telephony, multimedia and other
types of communications over the Internet.
9

Copyright © 2002 by Multi-Tech Systems, Inc.
All rights reserved.
4/02 86000461
Trademarks: MultiVOIP, Multi-Tech, and the Multi-Tech logo: Multi-Tech Systems, Inc. / All
other products or technologies are the trademarks or registered trademarks of their
respective holders. / Model numbers, product specifications, and prices are subject to
change without notice.
WORLD HEADQUARTERS
Tel: [phone]
[phone]
www.multitech.com
MULTI-TECH SYSTEMS (FRANCE)
Tel: +(33) 1-64 61 09 81
MULTI-TECH SYSTEMS (UK)
Tel: +(44) 118 959 7774
Who’s Multi-Tech?
Success is about communication.Multi-Tech is about
making it easier.We create better ways of sharing
information —remotely and over the Internet.
Multi-Tech solutions set the standard for efficient and
effective communication in an information-hungry age.
Our products are known for their reliability,performance
and flexibility.With Internet access, remote access and
telephony products,Multi-Tech is creating a world where
technically, everything’s possible.
At Multi-Tech we’ve built our reputation on reliable products
and our customer-centric approach —listening to our
customers and anticipating their needs.We also continue to
offer full-service technical support at no additional cost to
you; a policy almost unheard of in the industry.We provide
unlimited telephone technical support and 24-hour web site
support.You can rest assured that assistance and support
are just a phone call away.You’ll find responsive, technically
savvy professionals eager to answer your questions.