Comcast Telephone Service????

Hello all,

I have been reading and attempting to understand this issue of VoIP. I have talked some out of using any VoIP service because of all the problem expressed. Well it finally happened. I have a customer that decided to get his phone service thru Comcast Cable network. He indicated that he was told it will work with an alarm system. The panel is a NX-8E. So I asked him "is this VoIP??" He says what is that??? So I says Voice over IP. "No" he says, "I don't think it is." I says well we need to test to make sure that it can really work. So we test.................. six times total we send signals. And it worked every time.

So here is my question. What is Comcast doing or did we just get lucky?? Any all thoughts here would be very much appreciated.



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Digital Phone

The way the folks at Charter (the cable provider here) explained it to me was that the phone signal is only travels on the broadband connection from the house to the cable provider. From there it is returned to the normal phone lines. Something about that seems to not have the effect that true VOIP does.

Of course you are still facing the power outage issues.

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the house to the cable provider. From there it is

the effect that true VOIP does.

That's pretty much how VoIP works, too.

Reply to
Robert L Bass

I think that what Comcast is doing is just changing the name but it is still VoIP. I am presently on HOLD with Comcast to as some S-P-E-C-I-A-L questions. This should be fun trying to get some chickie babe to get out of the marketing script and give some good info. Will report what I learn, that is I can learn anything.

She is going to transfer me to "Tech Support".............................................

The "Digital Voice is not VoIP" They have a separate private network for the phone communication. Does NOT go out on the "Internet".

Being transferred again to the "Technical Support Team"..............................

"They do not have anyone that can answer weather or not there service will work with an alarm panel."

"Once the customer sets up for the service and a field technician is dispatched the field technician will determine if the service is compatible or not and inform the customer that it will not work."

"I can not be transferred to a dispatcher or field technician with out a customer number."

"No supervisor is available to provide me a number to call or have anyone call me to answer my questions."

I felt like I was beating a dead horse so I decide to quit. What a rat race. I really hate BIG Corporate America.

Well I have learned that ....................................... I really don't think I learned anything.

Anyone more successful and determining the truth. Or is this just a crap shoot.



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I don't think there is a definitive settled opinion within the industry just yet on VoIP or digital phone service. Most panels out there today weren't designed with anything other than POTS (PSTN) in mind. From the central station operators I have talked to fewer and fewer issues are being reported with VoIP or digital phone service. Even though your signals went through today, a change in the network might mean different results tomorrow. I think that is still an issue, the uncertainty factor. What that time table or percent failure rate is hasn't been something I have seen published. To test the panel six times in one day and claim victory might be a little premature.

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be fun trying to

info. Will report



work with an alarm

dispatched the field

customer that it

customer number."

me to answer my

I really hate

don't think I

Go here.....

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Comcast Digital Voice should work with most modern home alarm systems that use tone dialing and standard data protocols.* . Comcast Digital Voice service travels over Comcast's privately-managed network

- not the public Internet - which means you'll get all the quality and reliability you've come to expect from Comcast. . At your request, Comcast will install a hard-wired, dedicated feed between your Comcast eMTA (Comcast-supplied enhanced multimedia terminal adapter) and your monitored alarm panel. The Comcast eMTA provides up to 8 hours of battery back-up for Comcast Digital Voice service in case of a power outage at your home. . Please notify your home alarm company of the date and time scheduled for installation of your Comcast Digital Voice service, so that your alarm company can arrange to test your alarm system while our technician is at your home.

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Thanks for the link. I found this.

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Be sure to read A-L-L the FAQ's

Very interesting.

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I think you could get good results like that with just about any VoIP solution if you just test six times, so I think that was mostly luck. VoIP is really just another way of moving the audio data over the wire.

There are two things that makes our industry fret over VoIP;

1) Quality Typically VoIP adapters compress the audio signals digitally in a way that may distort them to a point where the receiving end can't decode the signals any more. Depending on what reporting protocol you use, this can be more or less of an issue. SIA uses different frequencies and encoding techniques than ContactID for example. Up/downloading can be really problematic. The VoIP box typically optimizes the compression to work well with human speech. Some VoIP equipment may have special algorithms for fax signalling or even modems, but our industry formats are non- standard, often designed to be easily decoded with dirt cheap hardware and are not recognized by the VoIP box. So the VoIP equipment tries to apply a voice algorithm to the SIA beeps, and out comes garbled data.

2) Reliability POTS lines are powered from a central point somewhere in your neighborhood. That station is the junction point for 100:s or 1000:s of households, and is equipped with a pretty beefy backup battery in case there is a local power failure. The VoIP ATA-box needs power from the residence and typically they don't come with any backup power option. The ATA boxes are not designed with power consumption as a high priority, so to back one up for 6-12h requires a pretty large battery. Depending on the network setup, the VoIP box may be hooked up behind a cable modem, DSL modem and/or home router. These also needs to be backed up for the system to work. Again, they were not designed for battery operation, so you may easily be looking at a total draw of 20-30W.

As much as it hurts, I think we have to accept that POTS is slowly going away. Even though most manufacturers have solutions to hook their panels directly to Ethernet, all the products I've seen are afterthoughts and ridiculously expensive. $200 for a network adapter? A NIC for a PC is $10 - and that's the good ones. Retail!

The only real way out here is panels that are network enabled out of the box AND making the Internet Service Providers understand the need of backed up & reliable connections.

Just my 2c.

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Comcast isn't VOIP per se. It doesn't use the Internet like Vonage does. It runs through a specific Comcast managed network that, theoretically, is much more reliable than Internet-based VOIP. ADT just released their new IP telephony regulations. They now allow communication via what they call Managed Facility Voice Networks, but not regular VOIP.

Here are their requirements:

What is a Qualified "Managed Facility Voice Network (MFVN)"? A Qualified "Managed Facility Voice Network (MFVN)": (1) has a physical facilities network that is managed and maintained (directly or indirectly) by the service provider to ensure service quality from the service subscriber location to the PSTN or other MFVN peer network, (2) utilizes similar signaling and related protocols as the PSTN with respect to dialing, dial plan, call completion, carriage of alarm signals and protocols, and loop voltage treatment, (3) provides real-time transmission of voice signals, carrying alarm formats unchanged, (4) provides professional installation that preserves primary line seizure for alarm signal transmission, (5) has major and minor disaster recovery plans to address both individual customer outages and widespread events such as tornados, ice storms and other natural disasters, which include specific network power restoration procedures intended to result in outage responses that are generally comparable to those of traditional landline telephone services in the same geographic region, and (6) has informed ADT that its network meets the characteristics of a MFVN.

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Not exactly, I got into an argument with a Comcast tech about it but they do have some differences over standard VOIP, apparently it does terminate to standard POTS lines and more often than not a panel will be able to send signals.

However I would still treat it like I would standard VOIP

Reply to
Mark Leuck

I found some interesting information on the net, which might help explain why some VOIP works better with alarm systems than others.

It seems that transmitting touch-tones is a known problem with some VOIP systems, and it has to do with the "codec" being used. The codec is the equipment or program that converts digital data into voice, and vice versa. Codecs based on the G.711 standard transmit touch-tones seamlessly, but they generate a 64kbps output. Other codecs, such as the G.729, compress things down to an 8kbps data stream, which apparently raises hell with touch-tones. Even when using a "full rate" codec such as the G.711, it helps if "echo cancellation" and "silence suppression" are turned off, but I have no idea who does that, or how. The 8kbps codecs presumably cost less and allow more calls to fit within the same bandwidth.

So, the key to determining whether an alarm system will work on a VOIP system may be to determine the type of codec that is used by the VOIP interface. Assuming the cable companies won't tell or don't know, googling the part number might produce some useful information.

- badenov

Reply to
Nomen Nescio

Ok, more info. At some point last night after the successful test the customer no long had phone service. Can you say crashed???

Today Comcast came out and determined that the modem (Motorola) was defective and they replaced it with a Arris Model# TM402P\\110. And the phone is working again. Sent signals to Central Station and all OK. Tried to Download to my office PC and again all OK.

I Googled the model number and the .pdf spec sheet indicated that it uses Codec G.711. So based on the info below this is good.

I asked my customer to do some regular test for the next few weeks.

He agreed. More info later.



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Silence suppression is a means of making a VoIP call sound more like a telephone call by creating background noise (BGN) similar to what is heard on a POTS call when no one is speaking. BGN is sometimes referred to as "comfort noise" because it makes the user comfortable that he is still connected. Needless to say, BGN is undesirable in a digital call between an aloarm system and the central monitrong station receiver.

Echo cancellation has been used on POTS phone systems for years. There is an inherent delay in processing long distance calls. The microphone picks up some of the receiver's signal and sends it back, a little bit later, creating an annoying echo. Echo cancellation systems are employed by telco's to kill the echo. The process typically employs two technologies. An adaptive filter picks up the echo, recognizes it as a delayed copy of previously transmitted waveforms (or, in more modern systems, bit patterns) and cancels most of the unwanted signal.

Adaptive filters are not perfect. They leave an aufdible component of the original echo (hmm; is "original echo" a contradiction in terms:))? A non-linear amplifier is employed to clean up what remains. The precise manner in which this is done is beyond my limitd knowledge of the subject but it involves suppression of the local signal and the remaining echo component.

One problem with adaptive filters and echo suppression apparently is they tend to see repetitive waveform (data signals are often repetitive) as noise and kill the signal. Also, some systems filter out high frequency sounds since they're not an expected component of normal speach.

Almost every ATA device's CODEC can handle DTMF (touch-tine) signalling. Becaue some alarm transmission formats employ DTMF, these may be better suited for use with VoIP service than others, especially pulse formats. NBo guarranty here that some particular unit will work. You just have to experiment.

Most major manufacturers list the CODEC's and lots of other stuff about their VoIP devices online. Worst case, you have to make a phone call.

Reply to
Robert L Bass

telephone call by creating background noise (BGN) similar to

referred to as "comfort noise" because it makes the user

in a digital call between an aloarm system and the

inherent delay in processing long distance calls. The

bit later, creating an annoying echo. Echo

typically employs two technologies. An adaptive filter

waveforms (or, in more modern systems, bit patterns)

original echo (hmm; is "original echo" a contradiction in

precise manner in which this is done is beyond my

signal and the remaining echo component.

to see repetitive waveform (data signals are often

frequency sounds since they're not an expected

Becaue some alarm transmission formats employ DTMF, these

formats. NBo guarranty here that some particular unit

VoIP devices online. Worst case, you have to make a

Amazing what a few seconds on "Google" will turn up, isn't it??

Reply to
Frank Olson

Not in the least surprising is the fact that you contributed nothing to the thread.

Reply to
Robert L Bass

Thanks for the info on silence suppression and echo cancellation. Do you know whether these settings can be controlled by user programming, or whether the VOIP provider has to do it? The information I read said that these two settings often cause problems for fax machines and modems trying to transmit over VOIP. Presumably, that also includes alarm panels that use modem formats.

Although codecs seem to be designed to handle DTMF signalling, that is apparently a different issue than end-to-end DTMF transmission. From what I gather, the basic 8 bit codec can handle DTMF signals from a touch-tone phone, but those digits are converted into digital data and sent out as part of the signalling protocol. By contrast, a DTMF device like a Contact ID dialer wants to dial the number (supposedly, not a problem for VOIP) and then transmit touch-tones end-to-end (which seems to be a problem for the 8 bit codecs). If true, this should be indicated at the digital receiver by transmission errors, rather than a failure to connect at all. I don't know whether codecs are even designed to support pulse dialing; I suspect not.

I am the first to admit my knowledge of this subject is extremely limited, so I encourage anyone with good VOIP technical knowledge to correct and elaborate.

- badenov

Reply to
Nomen Nescio

As long as Heinz continues to make beans in 14 ounce cans and Canada Rope continues to make 3/16" braided cord, I have no problem with communications... And our customer's calls are so clear you can hear a boulder drop. Our alternate communication path makes use of some very high tech bird food. Yeah, we do have to contend with a lot of messy poop on the station floor, but even that's significantly less than what I've seen you post here.

Reply to
Frank Olson

Where is that Jenny chick when we need her?

Reply to
G. Morgan

My understanding is that she installs/services telephones for one of the bigger "POTS" providers. Asking her about VOIP would be like asking Bass about programming a Napco LCD keypad. ;-)

Reply to
Frank Olson

It varies from device to device. My ATA device (which went bad so I'm awaiting a replacement) is configurable over TCP/IP. Just about everything in it can be changed. I sent it back so I don't have the model number but when it comes in I'll let you know. As I recall it was not expensive.

TTBOMK, none of them are intended for DACT pulse data (I assume that's what you meant rather than dialing).

Mine too, but I've had to study it a bit to learn what I need for my own offices here and in Brazil. WHat I do know is that it can be a royal PITA trying to figure out what's wrong when it fails. I'm working with some very knowledgeable techs who've been a real blessing in helping diagnose and correct things for us. Unfortunately, they're not exactly fast to reply when I ask for assistance. IME, that is still bettter than fast but dumb. :^)


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