Questions about low-pass filters (microfilters??)

[ugh]

Hi all,

I'll be getting DSL soon and I'm worried on where to place the modem since there are like 7 phones spread around my house using the same phone line. A friend told me that the modem MUST be placed before any splits to the phone line from the source. This really worries me as I have NO idea where the phone line is split first.

I then found out that it's possible to place the modem anywhere as long as I place low pass filters (they call it microfilters here) b4 all the phones that are connected to the phone line. Can someone please advise me on whether this can work? I'm really hoping that this would work as I really would not like to crawl around the ceiling (no attic here) and trace the wires.

Thanks in advance.

 

[Fallen Kell]

No the DSL does NOT have to be placed before any splits to the cable. You just have to be sure to place a filter on each of your phones in the house. The reason he stated it the way he did was because its easier to place the DSL before the splits. If you configure it that way, you would only need to filter the single line that goes past the DSL (i.e. line main phone line splits to DSL, after that split to the DSL, you just filter the main line after the split to the DSL which as a result filters the rest of the house).

The only reason for the filter is to keep the DSL signal from being transported to a regular phone. Without the filters, you can get inttermittent DSL connection as well as interference on the phones voice connection.

 

[Doh!]

There are recent modems designed for and does a pretty good job of preventing much disruption in the dsl connection when a phone call comes through. However, microfilters should alway help. My ISP provided me with 5 of them.

 

[dmcowen674]

If you have easy access to where you phone line comes in the house you may want to put a filter there. Go to DSLreports.com and there is a full report with pictures on how to do it.

 

[Fallen Kell]

dmcowen674: If he filters the phone line before the DSL modem he will not be able to connect using the modem. The filters, do exactly what their name implies, FILTER out the DSL frequencies.

 

[MrChicken]

It is generally accepted that 5 filters is the limit, past that you need to use a filter/splitter at the NID where the phone line enters the home. That is what you would get with a "professional" install. If you have phones daisy chained into a single phone jack, you just need one filter at the jack. Depending on how far you are from the CO, I would consider the pro install. A single unfiltered jack (in this case an alarm panel jack) dropped my connect speed in half.
OTOH, there probably is no harm in hooking up and trying it. If you are having problems, then call and have the pro install done.

Go to dslreports.com and read the FAQ's, there is even a how to for doing the pro install yopurself.

Originally posted by: ugh
Hi all,

I'll be getting DSL soon and I'm worried on where to place the modem since there are like 7 phones spread around my house using the same phone line. A friend told me that the modem MUST be placed before any splits to the phone line from the source. This really worries me as I have NO idea where the phone line is split first.

I then found out that it's possible to place the modem anywhere as long as I place low pass filters (they call it microfilters here) b4 all the phones that are connected to the phone line. Can someone please advise me on whether this can work? I'm really hoping that this would work as I really would not like to crawl around the ceiling (no attic here) and trace the wires.

Thanks in advance.

 

[dmcowen674]

Originally posted by: Fallen Kell
dmcowen674: If he filters the phone line before the DSL modem he will not be able to connect using the modem. The filters, do exactly what their name implies, FILTER out the DSL frequencies.

Most of the time you have 4 wire running in the house. You plug the filter in at where the Line comes in the house. Then on the filter you have a phone port and the DSL Port. You connect your regular home wiring run to the phone port. Then you connect the other set of wires to the DSL port. Then to go to the jack where your DSL Modem will plug into and make the alternate set of wires live for that jack instead of the normal wires. On a jack it is normally green and red. The alternate set is usually connected to black and yellow.

That is the easiest way to make a "Home Run" for the DSL signal instead of going through filters all over the house. For a true Home Run, run a new 2 conductoer wire from the DSL port on that filter you put where the Phone/DSL comes to the house and run it straight to the jack you will have live for the DSL.

Generally not a good idea to have more than 5 filters on a DSL line.

There is pictures of this at DSLReports.com FAQ