Channel Vision whole house DSL filter

The RJ31X requires a different type of filter. It plugs into the RJ31X jack and the 620 cable (which previously was plugged into the RJ31X) is plugged into it. These specialized filters for use with an RJ31X jack only filter DSL from the alarm system. They don't do anything for the house telephones.

Alternatively, you can install a splitter type filter at the demarcation point or anywhere else *ahead* of the phones and the alarm. This method filters DSL from all of the existing jacks save one. That one jack will be unfiltered. Cheesy ASCII drawing follows:

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I'll take a stab at it, knowing I'll probably be stabbed *for* trying, but hopefully a consensus might occur in subsequent follow-ups. (-: Your situation is similar to mine. I've got a separate phoneline which handles voice and the alarm panel and another line for DSL and voice as well. With the recent increase in rates, I am going to try dropping the second POTS line with the alarm connection and use the DSL line. I've been researching the issues involved in running an alarm through a DSL connection and have come across some consistent advice I'll attempt to relate without error!

An RJ31 jack is typically used a line seizure device. Since it's critical that the alarm panel is able to dial out immediately when an alarm is triggered, the RJ31 jack allows the alarm panel to disconnect any phone call in progress *downstream* from the jack and then grab a dial tone and dial out. That's why they are almost always the very first device connected to the phone network after the phone line enters the home.

DSL complicates the issues because some people want to be able to seize the voice line so the alarm can dial out WITHOUT interrupting their DSL connection (which could be relaying images from the house cameras that you might want to see remotely to confirm an alarm condition exists).

Which do you want to do? Is it acceptable to you for the DSL line to go down when your alarm dials out?

The RJ31 jack is larger than a regular RJ11 phone jack because the phone lines must be able to enter the jack, go into the panel, through the "line-seizure" switch, back out through the jack and finally on to the phone wires that serve the household phones. The reason for extra wire is that one pair is goes to the alarm panel and the other pair is used for wiring downstream to the house phones.

It depends. If the unit is already set up to seize the line in a case of an emergency, all you would do is maintain that wiring. But I am not sure what you are connecting to where. Let's start by ascertaining exactly what you are using. Is this it?

P-0411 ADSL Filter and Surge Module

It's got four incoming phone lines and a security system "Bypass/Normal" switch on the front.

Lots of potential problems. Static can be a grounding problem, oxidation on connections or just loose wiring. Or a lot more complicated.Let's start with a traceback from the Network Interface at the "Customer Access point (CAP)."

I'd probably start at the entry point, plug a phone into the network interface CAP jack to see what I heard and mentally gauge the interference level. Then I would split that line to a filter (you should have gotten a few RJ-11 filters with your DSL kit) and the other to the DSL modem. You should be connected to just that splitter and none of the other phone wiring in the home at this point. Not even the alarm. To troubleshoot this kind of problem, you really need to isolate components as much as possible from each other. The home phone wiring is a little like X-10 in that different types of devices have different impedances and electrical properties that can interact badly.

I'd make this test because you should now NOT hear any noise on the phone connected to the splitter leg that's got the DSL filter plugged into it. If you do hear noise on the voice side, you may have wiring issues outside of your control.

What you do from this point depends on your phone layout. I have a very, very primitive poor man's patch panel made out of a few phone harmonicas. I then run modular line cords (I got *such* a deal when the local HW went under) to each of the phones in the house. No phone jacks, just little modular cables coming from holes in the floor behind furniture tacked down with insulated staples. I use couplers and splitters to distribute the signal within rooms if need be.

It was a heck of a lot easier than installing wall boxes or even surface jacks since we thought we would only stay here a few years more -- that was a long, long time ago! I just had to make the hole big enough allow the modular clip to pass. No push down tools, no blocks - although I started that way.

The biggest advantage of this barbaric system (I can hear the catcalls already!) is that you can easily unplug one house phone at a time at the CAP to see which leg is screwy when there's a problem. Sure you can do that with blocks, but it took me 2 hours to run 8 phone drops and when I move, I suppose I could reclaim a lot of that gear. I'd glad I didn't spend much time on running POTS wires - the Uniden 5.8 cordless pretty much enables me to put a phone wherever there's an outlet for the charger with a single line running to the base station. Now the only cords that matter go to the PC for faxmodems and to the alarm and the emergency corded phones.

Anyway, I would see what I heard through the DSL filter right at the first split from the CAP. Let's get some more info for the traceback:

Do you have one or two or more phone lines?

Are they properly grounded? Lots of times phone grounds get loose or corroded and that can create a noise problem. At least inspect it visually if not with a meter just to make sure.

Is your Channelvision DSL filter mounted nearby and grounded as well? There shouldn't be any current flowing from the ground connection on the DSL filter to the ground connection for the incoming phone line.

There's an interesting discussion of how grounding issues can generate hum and noise here:

Do you want to be able to use any jack in the house for DSL or will there just be one or two phone jacks you will use for DSL?

A little more detail will help people in determining what to do next but the most important thing I can think of first is what I suggested. Disconnect

*everything* at the CAP and split that output to the DSL modem (just plug it in along with its power supply - no PC needed for this test!) and to ONE corded phone. If you still hear a hum, it's probably something the Telco boys have to deal with.

Once we get more information about the noise problem we can move onto to how to wire your jack correctly!

Is yours a self-install kit? That saves the Telco's boatloads of bucks but it often means that no trained technician ever looks at your entrance phone wires, which could easily be 20 or 30 years old with a badly corroded ground!

Tom_W - are you listening? (-:

-- Bobby G.

Bobby,

That's not necessary. If the gentleman uses the method I described earlier his DSL and his alarm will function simultaneously.

Actually, all of that could be done using a standard width jack with shorting bars. The reason the RJ31X jack is larger is it can accomodate two phone lines with line siezure. Because, as you rightly stated, each line needs 2 connectors for incoming line and 2 more for inside phones, the jack has eight terminals. The cord likewise, has eight wires and the plug is the size of a CAT5 plug.

Please do not do that. If you only connect red/green to the alarm you will defeat the line siezure function. That means all the thief needs to do is lift a phone or call the house and leave the phone ringing (old burglar trick) to block the alarm signal.

Given the gentleman makes no indication of a problem before he added DSL, I'd say those are not the likely cause. He's probably hearing DSL noise on the line. Proper filtration will eliminate that.

I took the following statement to indicate that he DID have a problem beyond proper DSL filtration:

As I stated, since it's likely he's got a self-install kit, it's possible a technician has not inspected the entrance wiring for years. Or even decades. There's not much harm and an awful lot of good that can come from simple inspection of the connection. The time to do that, IMHO, is before connecting every phone wire in the house to the telco's incoming line.

-- Bobby G.

Just to be clear, a filter needs to be before any POTS (Plain Old Telephone Service) devices like alarm panels and phones. The alarm panel (via the RJ31X) needs to be before the phones.

/-[filter]-[RJ31X]-[phones]

--[STREET]--| \\--[DSL Modem]

If the alarm tech is concerned about not being first in the circuit assure him/her that a DSL modem cannot take a POTS line off hook. At least I have never seen it happen...

The last drawing on the web page below explains this sort of setup. Substitute "filter" for "DSL Splitter" and you will get the idea.

Doh! I don't believe I left that out. Thanks.

Thankfully, DSL has been around long enough that by now most alarm techs realise what it is and know how to deal with it. In most homes they simply insert a plug-in DSL filter that's made for use with an RJ31X (alarm) jack.

Here are examples of a Splitter/Filter

and an alarm system DSL filter which I sell The splitter version is intended for use in an OnQ structured wiring panel. Stand alone units are fairly common as well.

I'll reply to all who answered below, since Robert has the most detailed reply.

I don't care if I lose the DSL when the alarm is engaged.

Yes I took the RJ31 behind the alarm apart to see what goes where.

Pins 1(White), 4(Red), 5(Green) and 8(Brown) are used. I'll just install a jack at the other end and duplicate the wiring. (Note to R.B., don't worry I plan to test it. :-) )

Yes, that's the one.

Makes sense. I want to eliminate the alarm from the circuit first (RJ31 at the filter), then I'll narrow down the source of the noise as you suggested. Just to be clear, there was NO noise before the modem.

Right now the return from the alarm is running into the filter and then out to the phones. So it's Alarm --> Filter ---> Phones, which not ideal, but I doubt it's the cause of my static. Although I've read that this can attenuate the DSL signal and my transfers are about 10% less than average for my area and provider.

Right now one, but two at one time.

Filter is a few inches from the incoming phone line. No way to ground the filter that I can see.

I actually located the modem beside the filter in the 'phone cupboard' and ran Cat5e to the router in the computer room.

Yes, it's actually DSL from a 3rd party, but the phone company did all the setup outside. This is about $15+ cheaper a month and the 3rd party has a good reputation. Although their installation documentation (none) made it interesting getting the modem-router to work behind the main router.