Difference between digital phone and VOIP

[JoeRaisin]

Anyone know the specifics?

 

[Anders]

Anyone know the specifics?

Short answer: Two names for the same thing.

Long answer: VoIP is one form of digital phone service.
Most "Digital Phone" offerings use IP and moves the data over
your regular Internet DSL/Cable/Fiber connection, so that makes
them VoIP by definition. Digital Phone Service *could* also mean
it uses a separate, dedicated channel and/or a different protocol,
but that's not common.

So in most cases the issues are exactly the same ;
- Power backup (if the cable/DSL modem and/or router is down,
the phone line goes with it)
- Latency/quality (it's a LOT better today than a couple of
years ago, but can still cause problems for control panels)
- User interference (users mess with the router, unplug wires,
change service..)
- Reliability (Internet Service Providers frequently cut off
service for hours at a time to do maintenance or upgrades)

If you hook up burg systems to VoIP/Digital, make sure both you and
the customer understands the limitations, or you will both be very
disappointed...

</A>

 

[tourman]

Ain't that the truth ! If a client comes to me for a new installation
and he has VoIP, I simply won't do it. If he changes later without
consulting me, he signs the liability of exclusion (up on my website),
or he finds another supplier - no exceptions!

The few VoIP installs that I have chosen to make work have all been
set for automatic daily tests. The daily reports on these systems I
watch like a hawk, and most will check in ok with the station about 5
days out of 7 successfully. The other two days...who knows.

I'm pretty hard nosed about this part of our business. Unless a
customer is serious about his security, I don't want his business
(besides, I'm also "cherry picking" these days - not looking to buy
troubles) VoIP is not yet IMO adequate for the job - maybe one day,
but not today. Besides, there are IP connection devices that are both
here now, and being developed, that promise reliability in the
future.

Personally, I'll wait until then......

R.H.Campbell
Home Security Metal Products
Ottawa, Ontario, Canada
www.homemetal.com

 

[Doug]

I could be wrong but I think that the difference is that cable digital phone
providers use their own cable infrastucture, while VoIP uses the public
internet

Doug

 

[Frank Olson]

I could be wrong but I think that the difference is that cable digital phone
providers use their own cable infrastucture, while VoIP uses the public
internet

Doug

I think you may be closer to the truth. I've had several customers
switch to Shaw's Digital Phone... With no problems on the alarm end
(and that includes downloading the panels).

 

[Robert L Bass]

Personally, I'll wait until then......

Bob,

Have you looked into any of the communications
systems specifically designed for IP?

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
941-925-8650
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
=============================>

 

[JoeRaisin]

I think you may be closer to the truth. I've had several customers
switch to Shaw's Digital Phone... With no problems on the alarm end
(and that includes downloading the panels).

But why does (Cable systems) digital work and VOIP has so many problems?

We don't have any problems with DSL (assuming filters are properly
applied) and as the name implies - that's digital also.

The downloader guys at CS are griping about not being able to hit
digital phone customers - but these are the same guys who want a tech to
go out to a site because the customer keeps answering the phone (they
don't bother to talk to the customer and explain anything, they want a
tech to drive out and do all the talking). They claim there is no
difference between the cable company's digital phone service and VOIP
systems.

I've tried to google it but all the explanations are vague and geared
towards selling the product.

 

[tourman]

Only in a cursury fashion to be quite honest. I am working closely
with a small development company in the process of designing an IP
communication unit called Lobenn. At the moment, they are going
through the lengthy process of getting ULC approval. I am one of
several alarm companies they interface with for information, trialing
equipment, and (in my case) the loan of alarm panels.

It would appear to be a decent unit; however, it will require a
specialized receiver at the station to transfer signals to the regular
receivers, so this may turn out to be somewhat of a "chicken and egg"
scenario. Big stations don't move too quickly, so it remains to be
seen about the "buyin".

I'm taking a "wait and see" approach to this whole thing, since I
don't want or need technical problems of that nature haunting me and
my clients.

RHC

 

[Robert L Bass]

Im taking a "wait and see" approach to this

whole thing, since I don't want or need
technical problems of that nature haunting
me and my clients.

Since I deal primarily with DIYers, I get more
calls from folks who are interested in experimenting
with new technology. I'm always on the lookout for
ways to handle things like VoIP, TCP/IP reporting,
etc. I expect we'll see a lot more development in
that area as the sunset clause approaches.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
941-925-8650
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
=============================>

 

[Doug]

I think that the cable systems digital service is closer to traditional
phone service than VoIP, it may be that it just uses a different medium
(cable instead of copper pairs) to transmit the local part of the call from
the subscribers premises to a central office. With VoIP, everything is
transmitted over the internet and problems arise because of varying speeds
in which the packets are transmitted and received. I'm just speculating
since I don't really know the answer. (RLB-insert stupid comment here).

Doug

--

 

[Robert L Bass]

But why does (Cable systems) digital work

and VOIP has so many problems?

There seem to be two problems that affect
signaling over digital lines. First is latency,
the time taken for a packet of data to be sent
travel and be received. The grerater the
latency, the more likely that the receiver will
decide the data is invalid. Some systems
are simply faster. However, even the fastest
ISPs can sometimes bog down during peak
usage hours (such as when Frank parses my
website... ).

Another problem has to do with the codecs
used by the VoIP provider. Codecs convert
analog sounds into digital data and back.
Some are very effective at handling DTMC
(Touchtone) codes such as are used by
Contact ID. Others are not. Obviously, if
you are using CID you'll want an ATA* device
that handles DTMF well. Many of the ATA
devices which handle FAX machines well
are also good with alarm signals.

*ATA = Analog Telephone Adapter.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
941-925-8650
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
=============================>

 

[Matt Ion]

Bob,

Have you looked into any of the communications
systems specifically designed for IP?

The catch with that, at least in residential, is that they still depend
on the reliability of the internet connection. Extended service
outages, customers mucking with cable/DSL modem hookups, etc. are still
just as much a concern.

 

[Jim]

I could be wrong but I think that the difference is that cable digital phone
providers use their own cable infrastucture, while VoIP uses the public
internet

Doug

--






- Show quoted text -

I also believe you're right.

Here, we have Cablevision. I've got dozens of people using their cable
telephone service. They don't call it VoIP or Digital telephone. They
refer to it as Optimum Voice. At a meeting they did say that they are
required to provide for other companies VoIP services, such as Vonage,
but they said that their service had dedicated bandwidth while the
others were allocated a narrower bandwidth which could vary depending
upon usage.

I've had some problems with downloading, but only with a couple so
far.

As far as I'm concerned, VoIP is working here. But .... I still have
my clients sign a waver.

 

[tourman]

Yes, for sure ! Customers messing around can screw things up big
time.!!

Also, these interface devices cost significant dollars and in most
segments of the residential market, price is a concern. In the "low
down up front, high ongoing contractual monthly" market segment,
perhaps this price can be absorbed, but in the "high up front, low
monthly, limited or no contract term" market, it must be absorbed up
front. And two hundred bucks is two hundred bucks !!

RHC

 

[Robert L Bass]

So VOIP can travel over the Internet, or over private wiring.

So one must always ask the question as to whose network
infrastructure is being used. VOIP and Digital Phone are
too general to define it...

Regardless whose network it is, VoIP can still cause problems.
Packet loss, latency and codec issues, as noted earlier, can
cause a loss of communications with the central station if the
alarm system is using analog (until recently virtually all were).

Unless you're willing to spring for a TCP/IP compatible alarm
system and unless you're working with a central station that
is equipped to receive alarms over the Internet, you may
miss signals from time to time.

One of the problems I've seen using certain ATA devices is
that they don't like short, quick bursts of DTMF (exactly what
the alarm system uses when sending CID). Even when I
dialed rapidly by hand at a rate no faster than 3 or 4 keys
per second, the devices would miss part of the dialing
sequence at least half the time. During an alarm call this
could cause a failure to connect or (worse) erroneous data.

I have not tried many of the newer ATA devices (only two
so far this year) but those I have used were still quirky.
Hopefully, things will improve over the next couple of years
as more and more businesses change over to VoIP, demanding
commercial grade services and 100% reliable hardware.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
941-925-8650
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
=============================>

 

[Carl Carlson]

Now here's an interesting article which is contrary to what the news
article said:

http://providentsecurity.typepad.com/community_security_the_pr/2006/07/shaw_digital_ph.html

Good article. Thanks, Sue.
js

 

[Robert L Bass]

The catch with that, at least in residential, is

that they still depend on the reliability of the
internet connection. Extended service outages,
customers mucking with cable/DSL modem
hookups, etc. are still just as much a concern.

I understand that and you're right to be concerned.
Unfortunately, this is the way things are going.
More and more telco's are switching their long
distance services over to VoIP for the same
reason homeowners are doing so -- it's less
expensive. I'm fairly certain that within a very few
years the major portion of telephony in this country
will be VoIP. Hopefully, QOS will improve as more
innovative devices are made.

Already there are a plethora of direct digital
telephone instruments on the market, including the
Polycom 501 SIP unit sitting on my desk. These
(or something like them) are the wave of the future.
This doesn't necessarily bode ill for the alarm
industry -- only for those who fail to keep up with
the times. [Note: No slight here to my friend, Bob
Campbell. He's getting ready to retire and move
to Florida anyway, smart guy that he is... :^)]

The question alarm company owners need to ask
is not "How do we keep people from switching to
VoIP," but "What must we do to be able to continue
providing services to them?" I believe we're seeing
the handwriting on the wall concerning phone
service. I don't pretend to know what the solution
will be but I'm certain we need to deal with it more
effectively than by simply warning customers of
the pitfalls. In case there's anyone left who hasn't
noticed, they don't always listen. :^)

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
941-925-8650
4883 Fallcrest Circle
Sarasota · Florida · 34233
http://www.bassburglaralarms.com
=============================>

 

[Matt Ion]

I understand that and you're right to be concerned.
Unfortunately, this is the way things are going.
More and more telco's are switching their long
distance services over to VoIP for the same
reason homeowners are doing so -- it's less
expensive. I'm fairly certain that within a very few
years the major portion of telephony in this country
will be VoIP. Hopefully, QOS will improve as more
innovative devices are made.

Oh, I would fully expect so. Enterprise phone systems have been using
VOIP for years, since before the "VOIP" buzzword was coined... often
only internally, between the desk sets and their switching unit, but
it's the same basic technology.

It's like anything else in technology: what you see at the low-cost,
mass-market consumer level pales in comparison to what's really
available in features, functions, scalability, and reliability... it's
only a question of cost.

Consumer devices will certainly improve as the technology filters
down... it's only a question of how quickly.

The question alarm company owners need to ask
is not "How do we keep people from switching to
VoIP," but "What must we do to be able to continue
providing services to them?" I believe we're seeing
the handwriting on the wall concerning phone
service. I don't pretend to know what the solution
will be but I'm certain we need to deal with it more
effectively than by simply warning customers of
the pitfalls. In case there's anyone left who hasn't
noticed, they don't always listen. :^)

I don't think we need to worry about VOIP becoming the "de facto" of the
major providers until that technology IS reliable. The big backbone
providers (Ma Bell and family) can't afford to dump everyone over to a
new technology until it's achieved a certain level of reliability... I
dunno about the US, but up here, if reliability levels aren't
government-mandated, they're certainly government-encouraged. Telus,
for example, couldn't just start pulling up landlines and pushing
everyone onto VOIP if it weren't 99.99% solid - not only would the CRTC
not allow it, the public outcry would force all levels of government to
intervene.

 

[Beachcomber]

But why does (Cable systems) digital work and VOIP has so many problems?

We don't have any problems with DSL (assuming filters are properly
applied) and as the name implies - that's digital also.

The downloader guys at CS are griping about not being able to hit
digital phone customers - but these are the same guys who want a tech to
go out to a site because the customer keeps answering the phone (they
don't bother to talk to the customer and explain anything, they want a
tech to drive out and do all the talking). They claim there is no
difference between the cable company's digital phone service and VOIP
systems.

I've tried to google it but all the explanations are vague and geared
towards selling the product

Digital signals sent over a cable network generally use proprietary
equipment that is provided for and maintained by the cable company all
the way to the head-end or switching center.

VOIP is based on the principle of sending packets of data over public
networks and (hoping) that they eventually get to the right place and
assemble themselves in the correct order. The Internet companies
don't care about the integrity of the data packets. They just pass
them along as routine data.

Thus, over a period of time, links will go dead, cables will be cut,
etc. Perhaps redundant circuits will kick in... perhaps not.

There was a recent news story about fishermen salvaging undersea fibre
optic cables in Thailand (the cables contain valuable metal conductors
to power the repeaters). It shut down most of the Internet links to
that country for weeks. Bad fisherman!

The big phone companies traditionally have had the incentive to
maintain their links, and provide redundant links should the main
circuits go dead. They could afford to give good service because they
were paid to do so.

These new breeds of VOIP Telcos just digitize the information and put
it on the public Internet, sort of like e-mail. It will probably get
there, eventually, hopefully, but don't ask for a guarantee. And...
if not... to whom do you call to complain to?

 

[Anders]

But why does (Cable systems) digital work and VOIP has so many problems?

We don't have any problems with DSL (assuming filters are properly
applied) and as the name implies - that's digital also.

Even if you normally don't have any issues with your Internet
connection while surfing the web or emailing, you may run into
problems using VoIP.

This is because VoIP needs a constant stream of data to carry
the audio data. The voice data is chopped into "packets", each
packet holding maybe 50-100ms worth of audio, and sent on its way.
If some of those packets get lost, the system tries to "guess"
what should have been there, and that actually works pretty
good. The human brain also has a tendency to fill in the gaps so
most people don't even hear a few lost packets.
A control panel modem is not as forgiving.

The latency is also a result of this "packetizing". When a packet
leaves the VoIP-box, it comes to the router. The router needs to
receive the WHOLE packet to make sure the checksum is good before
it sends it on to the cable modem. The cable modem again needs
to get the whole packet before it moves on to the cable, and
so it goes for every piece of hardware between you and the
destination. You can get a feeling for how many "hops" you have
between yourself and a destination by opening a command prompt
and typing :
tracert www.google.com
(or whatever destination).

Like someone else wrote in this thread, the voice streams
share the same bandwidth as all other data on the Internet.
If your YouTube video download halts for a second, you'll not
notice it because the pre-buffer for several seconds, but 1s gap
in a voice call is really annoying.

Some of the cable bundles allocate separate bandwidth for their
own VoIP, and there have even been rumors about them *limiting*
the bandwidth or intentionally dropping data when they detect
competing VoIP packets on their network. Thus it may appear as the
bundled VoIP works better than for example Vonage.

So the bottom line is that VoIP is designed for VOICE. Not the
bleeps and burps a control panel spits out when it communicates.
A panel designed for networking, bypassing the VoIP modem, will
work a whole lot better than one using VoIP as a POTS replacement.
Not to mention the possibilities of having direct remote access
to the panel and the ability to supervise the connection for
"free".

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