Not quite true (as kraftee says later) The 'modem' side of a filter should (on decent units)have additional components in it to isolate/protect the modem from the DC on the line, the 25c/s ringing voltage and the dc changes caused by lifting/replacing the handset on other phones.
Mike
No. Any components there may adversely affect the line balance and impedance. All the required 'protection' is in the modem itself. It would be nuts if it wasn't.
Graham
Not necessarily.
However I suspect the cost of the odd blown modem is a lot less than trying to distinguish between a 1Mhz signal and a lightning transient, without making the modem cost £1000 and therefore not be saleable.
I had USR 9600 modem that DID get literally struck by lightning: they replaced it FOC. I queried this and they said 'its built into the price. Its easier to simply replace blown units with no paperwork and invoicing, than to fiddle about trying to determine if the customer is lying, and its a heck of a lot cheaper than trying to proof them against it. We strip out the guts and scrap any parts that don't work: In your case sir, probably the whole thing"
But as far as the typical ADSL unit goes, part of what it does is to have a high pass filter of probably at least second order set at about
20Khz: That's more than enough to get rid of any DC, speech and ring tone on the line. All you ant is to reduce it so it doesn't overload the digital filters that come later.So you just plug em straight into BT and Robert is a relative.
If the modem has a phone port, that will have its own low pass filter in it. Another reason why you wouldn't want to do that sort of filtering higher up the food chain: phones plugged into a phone socket on the modem would NOT then work.
The other reason for using a filtered Master Socket is that then the ADSL signal gets taken off the line as soon as possible and doesn't get fed on to all the sockets around the house with possible mis-termination and standing waves upsetting the signal. I know people will say "what about the crappy BT joins outside your house" but at least they usually stay the same.
Mike
: : The other reason for using a filtered Master Socket is : : that then the ADSL signal gets taken off the line as : : soon as possible and doesn't get fed on to all the : : sockets around the house with possible mis-termination : : and standing waves upsetting the signal. : : I know people will say "what about the crappy BT joins : : outside your house" but at least they usually stay the : : same.
So what if you need the ADSL signal at a socket other than the master..? My router/modem is in an upstairs bedroom, it would not be practical to locate it at the master socket.
Ivor
Fit a filtered faceplate at the master socket, and run cat5 cable from its RJ45 socket to another RJ45 socket at a convenient location. Plug your router into the second RJ45 socket. The Cat 5 cable will ensure that the ADSL signal arrives at the second socket substantially uncontaminated.
Or, put your router beside the master socket and work out a networking solution to your computer (upper room). Network could be ethernet (same as Graham J's method for cabling); wireless (depending on wall count), ethernet over mains (pretty effective every time I've seen it used, Solwise.co.uk for reasonably priced components).
It is worth finding out how much you loose through your house wiring on your BB speed. Some people loose immeasurably little, others find half their speed is lost in the poor wiring around their house.
- Nigel
Or buy a SSFP with 2 sets of isc's on the back, one for you extension wiring & one for your DSL signal, but you would still need good quality telephone cable to get the signal to where you want
: : : : So what if you need the ADSL signal at a socket : : : : other than the master..? My router/modem is in an : : : : upstairs bedroom, it would not be practical to : : : : locate it at the master socket. : : : : : : Fit a filtered faceplate at the master socket, and : : : run cat5 cable from its RJ45 socket to another RJ45 : : : socket at a convenient location. Plug your router : : : into the second RJ45 socket. The Cat 5 cable will : : : ensure that the ADSL signal arrives at the second : : : socket substantially uncontaminated. : : : : Or buy a SSFP with 2 sets of isc's on the back, one for : : you extension wiring & one for your DSL signal, but you : : would still need good quality telephone cable to get : : the signal to where you want
Sorry to burst everybody's bubble, but my system works perfectly well with el-cheapo plug-in filters at the master and extension sockets. Plus the router (which has built in VoIP and LED's that I want to be able to see) can be where I want it.
Ivor
Pity you didn't read Nigels post. If you had you would have already known that you wasn't going to burst anybodies bubble...
: : : Sorry to burst everybody's bubble, but my system : : : works perfectly well with el-cheapo plug-in filters : : : at the master and extension sockets. Plus the router : : : (which has built in VoIP and LED's that I want to be : : : able to see) can be where I want it. : : : : : : Ivor : : : : Pity you didn't read Nigels post. If you had you would : : have already known that you wasn't going to burst : : anybodies bubble...
I did read it, he said run CAT5. I don't want or need to.
Ivor
In the first paragraph I gave three options for linking back to a master socket.
In the second paragraph I wrote: [quote] It is worth finding out how much you loose through your house wiring on your BB speed. Some people loose immeasurably little, others find half their speed is lost in the poor wiring around their house. [quote]
Evidently you think you are loosing so little that doing nothing is sensible. Others will find a certain amount of loss, and have to decide if its worth networking to the master socket to remove that loss. In extremes its the difference between a stable broadband service and no connection.
- Nigel
The ADSL connectors on the master socket/modem are actually RJ11 with the line on the centre pins. One can now buy long cables terminated in RJ11 both ends for this very purpose. I guess PC world will charge about £100 whereas Maplin will be much cheaper at £10 for a 10m cable (A93CG) or less for shorter. Or an 'ultra high speed version for £20 (A97CG) CPC even cheaper.
I used to always pick up a few when I was in the US/Canada before they became available here
Mike
Yes, I got a 15m one MUCH cheaper at CPC (I don't use it any more; router and rack are 1 metre from the master socket!)
Having said that, a twisted pair cable will be better in many cases, as a house is inherently a 'noisy' place.
Yeh but it still requires RJ11s unless one wants to wire from the back with CAT5 and that is probably only better than standard (modern) BT twisted pair cable cos it is thicker and hence less lossy.
I doubt it is possible to get RJ11 terminated CAT5 unless one makes it oneself and manages to get the thicker cable into RJ11s
Mike
Standard BT twisted pair was really all I meant. Most extension leads seem to be flat twin.
ADSL Nation used to do a range of what they called ADSL2 extension leads, RJ11 plugs on the end & (lovely) twisted pair inbetween & if my memory serves me well the longest was 20mtrs, which should fill anybodies needs..
[FX: waves]
The internal phone wiring in my house is so pants, the broadband wouldn't work. We got a filtering master socket and all is well.
It was convenient that the master socket was in my study - it is, as someone has said, useful to be able to see the modem.
My modem feeds 4 RJ45 sockets around the house. Wireless was a bit expensive when I installed it. And I'd rather not have to look at all that wiring so I fitted it in the cellar - which is where I re-routed the phone line to enter the house, rather than the original through a window frame. ;-)
If I suspect a problem with the router I can interrogate it from any computer on the LAN, and re-boot if necessary.
Don't give your address Dave or Gippy Joe will be around to tell you off!
Mike (When I had my ISDN Home Highway installed, the BT man was over the moon that I had pre-installed a nice new cable from the block outside to inside to the new socket position for him!!)
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