atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Security, Alarms and Paging Alarm line

Hello there techs,

So here my ?. I was a jobsite today, adding a jack, customer has DSL, tried putting a splitter
filter connected phone a got data/noise on line when using line, I toned the cable and found that they have an alarm (reg & cell) so I found that the alarm is wired only to incoming line and not sending out to phones, the cable I toned was wired directly to MPOE. I made a second jack
and attached filter to this w/ phone and had no trouble, but if I put a splitter filter w/ modem on same jack I get the noise. Is this something that may be caused by the alarm wiring and will I have any trouble down the line, the way I wired the jack today directly to MPOE w/ alarm as well from MPOE?

Thanks!

I have no idea what you are trying to say but I'll put it to you this way- everything on a DSL line MUST have a filter before it EXCEPT the modem. So if you are using a splitter filter, the phones and alarm are connected to the filtered side. The modem gets connected directly to the line side (or MPOE).

-Hal

Thanks Hal!

Whoa. Here is a dilemma:

The alarm, by rule, needs to be connected as the FIRST device after the NID, and then feed the line back to ALL other devices on the premises.

The alarm communications circuit cannot operate reliably on a line with DSL noise.

However, the DSL filter needs to be wired BEFORE any voice device (including, in this case, the alarm dialer), so that the DSL signal pair is split off, unfiltered, and sent directly to the modem.

Therefore, we have a conflict.

From a strict interpretation, an alarm panel cannot be used on a line that has DSL. If the DSL filter fails, or the modem goes crazy and locks up the line, then the alarm is left with no communication ability, and its line-seizure feature is compromised.

Further, if this is a commercial facilty with a UL-approved alarm, the panel needs to have TWO lines, one dedicated, and one non-dedicated. The dedicated line, if we agree on the above, cannot be a DSL line.

This is a very interesting case.

EDIT!!! This just in from my local alarm guru:

DSL filter

This solves the above problem.

Arthur nailed it with his edit. The first device needs to be the alarm panel with the proper filter installed, I use the one Arthuer referenced. Then it can come out of the panel and you can do what evr you would like with the line.

Yes, they do make a "RJ-31x" DSL filter. However the OP stated that there was no feed through the panel- only its T/R was connected to the line.

So from his point of view he is not going to reconfigure the alarm panel, only reconnect it the way it was so that everything works. I would do the same thing. If the alarm guy connected it that way I'm not going to change it.

-Hal

can;t blame you for that Hal, the alarm installer should have done it right the first time.

I like the approach that the alarm guy should do his job correctly, too.

The problem, in these litigious times, is that if a building burns down, the alarm fails, and the insurance guys and the arson squad find out who the last person was who worked on the telephone/alarm wires, and it is was you, there will be a lot of expensive finger-pointing.

I used to do alarms, until the licensing and insurance fees became so expensive. When I encounter an incorrect alarm installation, even though I'm not licensed to work on them, I either call the alarm company (in my area I'm known to pretty much all of them) and explain the problem, and offer to fix it for them on the spot, or I get a firm commitment from them, on behalf of the customer, that they will be out quickly to fix it themselves.

I also get a dated, signed acknowlegement from the customer that I have found a problem with the way the alarm is wired, and that they are aware of it.

I have talked this over with alarm companies whom I know, (who 100% of the time appreciate my input and concern) and with my own insurance company, and they concur that being the last guy there, and NOT reporting the problem, is potentially going to bite me.

Here's how my DSC alarm is wired:

CO -> Filterd DSL -> Alarm -> KSU/SLT's
CO -> Unfiltered DSL - > Network

They make a DSL filter that fits into the NID, with filtered and unfilterd outputs. They put it in when I got UVerse.

Before that, I used a standard DSL filter in it's place, which has both filtered and unfiltered outputs. I'd cut the jacks off of it and wired/stored it inside the NID in my basement. The outside NID simply feeds my inside NID directly.

You can't really read it, but R/G are POTS, Y/B are DSL.
NID Filter

we do a lot of them and use a DSL splitter

we come in from the telco to the splitter

out to the dsl modem

then take voice out to a block where the alarm co can grab it (or we wire the rj31x) for them

I like to put a tie wrap on the splitter to keep the alarm guys from trying to go inside and grab the line first