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Topic # 29542 11-Jan-2009 02:07
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I'm relocating to Wellington and hope to use TelstraClear for my Internet, and continue with 2Talk for my VOIP. That means I won't need a phone line.

Has anyone else using VOIP exclusively solved the issue of monitored alarms? We'll be moving into a brand new house, so I can choose the alarm system. Are their alarm systems and monitoring services that are all Internet-based?

I hear going the ATA route with alarms can be a bit hit and miss because of how rapidly many of the systems expect the DTMF to be sent and received.





Jonathan Mosen

 

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  Reply # 188715 11-Jan-2009 08:58
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IP based alarm systems are now pretty common and there are also addon units available that attach to the phoneline output on panels that  Contact ID (one of the most popular alarm protocols) and convert this to ethernet so it can run over the net.

The problem at present seems to be the serious lack of monitoring companies who support IP based monitoring. It's obvious many are in total ignorance of the changes that are happening in the communications marketplace.

My suggestion would be to give the guys at AlarmNZ a ring. They do IP based monitoring also also have a lot of IP equipment so I'm sure they could give you some more information.

Contact ID is just a DTMF based protocol so does work well over a good quality connection. A poor connection however and it will cause issues. Some other alarm protocols are essentially modem based and will encounter issues. If you are installing a new alarm then I'd go straight towards an IP based solution or look at options for cellular units.




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  Reply # 188995 12-Jan-2009 15:11
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I'm using a linksys router that has 2 voip ports on it, they connect back to vfx, one of the lines has my alarm plugged in and I'm monitored by safesecure, all working well




Barry Murphy
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  Reply # 189660 14-Jan-2009 23:54
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Likewise with my alarm. Have just moved to XNet Fusion and I have the alarm connected to the Trixbox via an SPA3201 ATA device and the alarm dialer was quite happy to find a dial tone and dial the monitoring company.  Immediately after disconnecting the PSTN trunk, the Alarm displayed a "Lost Trunk" system fault, but that cleared by itself the following morning when it perfomed its scheduled "phone home".

Cheers Mike

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  Reply # 190340 18-Jan-2009 11:37
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Interestingly, this issue (use of VOIP trunks for alarm monitoring) is not resolved for me.

Initially, I assumed that because the Alarm system had cleared the system fault indicating that it had restored contact with the monitoring company, that the VOIP trunk was workling correctly. However checking with the monitoring company and reviewing the call logs reveals that the calls from the Alarm were place and answered and lasted for up to 20 seconds each time, the data packet from my alarm is not getting through.

It would be interesting to understand why the data is not getting through.

Apparently its a well known issue and my monitoring company is working on a fix i.e. a fix to allow VOIP based trunks rather than IP monitoring.

Cheers Mike



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  Reply # 190342 18-Jan-2009 11:54
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The reality at the end of the day is that using an POTS based alarm dialler over VoIP is a best effort scenario. I don't think anybody can guarantee this will work 100% without issue. IP based monitoring is the solution but unfortunately most alarm companies seem to be completely ignoring this and don't support it - any monitoring company who doesn't support IP based monitoring or looking towards implimenting this in the near future is going to find their customer base leaving them very quickly as we move towards a VoIP world.

Do you know what type of alarm panel you have and what protocol it uses? Contact ID is used by a large number of panels and uses DTMF tones to send the signal. Providing you have a good VoIP conection with minimal jitter this will work. Many other alarm protocols are modem based and simply will not work over a VoIP connection.

The lost trunk issue is caused by the alarm continually monitoring the line for a tamper situation however the characteristics of the ATA's FXO port is different to the alarm believes there is a line loss occuring.

Adapters to convert ContactID based panels to IP are around ~$200 and simply have a conector for the POTS output from the alarm and an RJ45 connector at the other end. These then use the ContactID protocol over IP. To use this however you need to be with an alarm company such as AlarmNZ who do IP monitoring. I personally would never bother with trying to use an alarm with an ATA and would go straight for an IP based solution whether by way of an IP based panel or IP adapter.



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  Reply # 190347 18-Jan-2009 12:28
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Thanks sBiddle,

The alarm is a NetworX NX-4 system but i do not know what protocal is used for the POTS connection. Is the issue one of bandwidth?   Certainly when I called the dial in number myself, I had a very clear connection, but of course, that was just to my ear, the data circuits could very well be having a different experience. 


PS The trunk it is hooked into, goes to an SPA3102 then on to a Trixbox installation. Would a different ATA be worth trying or are there any values in the SPA3102 that could improve things - such as the Network Jitter Level?

Cheers Mike


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  Reply # 190360 18-Jan-2009 12:58
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From what I can see the panel does ContactID.

What codec are you using for your VoIP connection? G729 or G711? I assume you are using RFC2833 for the DTMF back to WxC?

As a suggestion try using inband in the DTMF settings in the SPA and the extension you are using. I've only spent a few hours in total playing with alarm stuff over VoIP but found that a SPA would communicate fine directly back to WxC but using the same SPA via trixbox had some issues. At appears there are issues with the speed of the DTMF tones using ContactID if you try and use RFC2833 between the SPA and trixbox but I found inband seemed to work fine since it wasn't doing any conversion to RFC2833. Also try adjusting the jitter levels to low in the ATA since being on the same LAN there should be minimal jitter issues. You will also have to be using alaw/ulaw between the SPA and trixbox as inband DTMF won't work with compresses voice codecs.

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  Reply # 190418 18-Jan-2009 19:15
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Thanks sBiddle

Appreciate you taking the time to help.  The SPA3102 is set for a Preferred Codec of G729a. I have changed the Jitter Level to Low and set the DTMF TX Method to INBAND.  Neither of those last two options were set that way. I have also changed the codec to G711u (ulaw).  I will let it attempt its next call in and assess the effect.

Interestingly, just checking the VFX Trunk setting, the dtmfmode=rfc2833 was not defined. I have also loaded that entry in the trunk PEER Details.

Cheers Mike

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  Reply # 190421 18-Jan-2009 19:54
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If you are using inband in the SPA just make sure you change the extension settings in trixbox. This is probably set to RFC2833 so you will need to change this to inband. You can also use "auto" which will apparently detect inband if the device doesn't indicate support for RFC2833 but I've never used this option.

Let me know how you get on, it's something I'm interested in but haven't really spent a lot of time playing with.


You alarm probably dials out on set and unset and probably had a button combination to test the line as well if you ask the monitoring people they could probably help you.


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  Reply # 190443 18-Jan-2009 22:51
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Great thanks - I have changed the dtmfmode entry in Trixbox for the extension used for dialling to inband.  I will check with the monitoring people tomorrow after its scheduled nightly call in tonight and see how things went and report progress.

Cheers Mike

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  Reply # 190485 19-Jan-2009 10:53
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No luck with G711u (ulaw) so I will try again tonight with G711a (alaw). Could not even get a completed handshake on the last attempt!

Cheers Mike

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  Reply # 190486 19-Jan-2009 11:02
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mruane: No luck with G711u (ulaw) so I will try again tonight with G711a (alaw). Could not even get a completed handshake on the last attempt!

Cheers Mike


alaw and ulaw are virtually identical so it won't make a difference. One is the US/Japanese IDSN voice codec and the other is for Europe and the rest of the world.

Have you asked the alarm company what protocol they are using for your panel? If they are using ContactID maybe they could change the panel to SIA which the panel does support?



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  Reply # 190582 19-Jan-2009 18:51
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Ah good question for them - thanks will check that out tomorrow.  I knwo that they are working on a VOIP option so perhaps that is they have in mind.

Cheers Mike

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  Reply # 191071 21-Jan-2009 15:10
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@sbiddle

Apparently the monitoring company does support SIA but I am still waiting to see how and if they will implement that.

In the meantime, I was unable to complete a data transmission using Network Jitter=Low in the SPA3102 and dtmfmode=inband in the Trixbox extension configuration.  The call logs show numerous attempts all lasting less than 10s indicating that the dialer could not complete the handshake.


I changed the SPA3102 Network Jitter option to Medium and the Trixbox extension dtmfmode=auto and the dialler was then able to complete a handshake and pass the communication parameters i.e. event id etc.  However, it was not able to complete the call-closing handshake so the call was recorded as two events by the monitoring company i.e. the true event plus a communication failure.


I will increase the network jitter level to HIGH and see if that improves the ability to complete the communication.  Otherwise, with these settings, it is able to call the monitoring company and pass an event code, which is better than it was.

Cheers Mike


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  Reply # 191127 21-Jan-2009 19:20
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There is a need for a low cost gprs or umts monitoring service - I know that its available for car alarms for not a lot, but noone is offering it on home alarms other then seriously expensive commercial alarms.




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