Tech Tips: NBN & Alarm Reporting

28 Oct, 2020, 12:04 PM

In the last week, I have been asked at least 4 times about alarm reporting & the NBN.


My answer is always the same…. as a general rule NO.


There are a number of reasons I take this rather strong stand.


Firstly, almost all alarm panel diallers report utilising a format called Contact ID, often abbreviated to CID. This format utilises DTMF tones for alarm information reporting. As the NBN is just a big VOIP system, yes including the Uni-V ports, it will at times have issues. At times your alarm reports will not get through due to the length of these DTMF tones being changed as they pass over the NBN network.


The worst part of this issue is that it will probably work some or even most of the time, so if you are testing at 2 pm, when there is not a lot of internet usage, then it may be fine. But when the alarm is activated at 7 pm when everyone is downloading/watching Netflix etc it may not work. This is due to the higher network (NBN) utilisation leaving less bandwidth for the voice channels. This leads to greater distortion of the length of the DTMF tone. There is only a 5% variation allowable in the nominal 100mSec DTMF tone length.


The next obvious solution is to utilise one of the many add on IP reporting modules, and plug that into your clients NBN connection. On the face of it, this is a much better solution and in many ways it works very well, however, there are still some pitfalls to be aware of.


1. Battery backup on the clients’ premises. All of the clients networking devices between the alarm panel & the NBN require battery backup on site. This includes any network switches, routers & modems.


As AS2201 requires us to supply a minimum of 16hrs battery backup then it would be reasonable to assume that this would also be required for the UPS (s) that you would utilise on the clients’ network equipment. You will also need to ensure the client does not plug their computer or any other equipment into this UPS and reduce the run time of the UPS.


2. NBN side battery backup. Large portions of the NBN network have limited or no battery backup on the NBN side, eg HFC delivered NBN has no battery backup on the amplifiers etc. I have been told that the typical battery backup capacity for the majority of the FTTN NBN rollout is limited to 2Hrs.


3. As the clients networking hardware is accessible to them / their IT. It is possible that they can change the configuration to stop the alarm gear from having internet access. Or as it may be that the relevant patch lead is unplugged.


My personal recommendation is to use some form of multiple path solutions which incorporates at least one 3G / 4G path along with an IP path. Something like a Permaconn or an AAP 35 IP / SMS unit.