Internet Modem Cable

Bradfield

Hi Folks,

I have been trying to configure an ADSL (wired) router for a few days now and there is one thing I have noticed which I find difficult to explain.

I have several Internet Modem Cables (RJ11/BT Plug). They all look as if they are designed to do the same job (connect the router to the BT mains). However, I am finding that most of them do not seem to work. Of six modem cables, maybe two will work and four will not.

When I attach a modem cable to the router I first get a flashing light which, according to the manual, is the "ADSL training in progress". When the light stops flashing "an ADSL link has been established and is ready to transfer data".

Of the six modem cables' that I have attached only two attain the second stage of establishing the ADSL link and the other four continue flashing ad infinitum.

This also happens with a second router that I have so I have to suspect the cables rather than the routers.

Is it usual for these modem cables to malfunction or is something else happening here that I am not aware of.

Welcome any advice.

fwor

Do you know for sure that they are modem cables and not phone handset cables?

Reason I ask is that the two are not wired the same. IIRC, the RJ11 on a handset has the two inner and two outer wires transposed.

Bradfield

fwor wrote: »

Do you know for sure that they are modem cables and not phone handset cables?

Reason I ask is that the two are not wired the same. IIRC, the RJ11 on a handset has the two inner and two outer wires transposed.

I cannot speak for the others but I did buy a cable today which is clearly identified as an Internet Modem Cable. It does not get past the flashing light stage.

I will try it again tomorrow to see if it is still the same

grizzly1911

You are using a filter?

Bradfield

grizzly1911 wrote: »

You are using a filter?

Yes! Not directly in the main BT socket but at the end of a 5M extension cable. The modem cable is then placed in the filter. This works ok for two of the modem cables.

GunJack

^^^ but that may well just be that those 2 are not increasing the attenuation past unuseable.... if you really can't live without the 5m extension cable, try double-filtering it, but I suspect you need a 5m ethernet cable and move your router closer to the master socket - any phone extension is not good for broadband signals

Figment

Bradfield wrote: »

I cannot speak for the others but I did buy a cable today which is clearly identified as an Internet Modem Cable. It does not get past the flashing light stage.

I will try it again tomorrow to see if it is still the same

AFAIK there's three types, all different: phone handset, modem (dial up) and modem (ADSL)

Enterprise_1701C

Bradfield, are they old cables? These cables do get damaged or stop working for seemingly no reason, we have seen this happen several times.

You say you are using an extension cable? It is possible to run a modem off an extension lead, but you would be far better off having it plugged straight into the socket and run a longer Cat 5 cable to the computer (sorry - I see GunJack has already said that).

Have to say I do not think it is a good idea to double filter it though!

Bradfield

Many thanks for the very helpful and informative replies.

I was not aware that there were different types of cable for telephone and adsl. They all looked like adsl cables to me and I just assumed they all did the same job. I guess I was just wrong.

My router is currently based about six or seven metres away from the main BT socket. I could place it nearer the socket and use a 10 metre ethernet cable to connect it to the computer.

I have taken on board all the advice re filters and extension leads.

What I am going to do now is to move the router nearer to the BT socket and test all the cables that I have. I am going to clearly mark the ones that do the job and discard the ones that do not work.

Also, I have decided to keep away from the cheap cables and buy good branded products. It is amazing that these cables do such an important job and yet, in the past I have been happy to buy them cheaply at the Pound type shops.

Dave_C_2

Bradfield wrote: »

I have several Internet Modem Cables (RJ11/BT Plug). They all look as if they are designed to do the same job (connect the router to the BT mains).

If you are trying to connect between phone socket and router using one of these:

Then you are doing it wrong. These cables are to connect telephones and faxes. The reason some work and some dont is that there is no standard of connectivity at theRJ11 end. They are not made to be replaced - you should not be able to unplug the lead at the telephone end. So saying, the rules may have changed since I left the telephone design industry.

Plug an ADSL filter

into the phone socket (preferably the master socket) then connect the filter to the router using an RJ-11 to RJ-11 modem lead.

The phone goes into the other socket on the filter.

Finally connect to your PC from the router using an Ethernet patch lead


Ideally, the connection to your router should be as short as possible, no more than 2 metres. The Ethernet patch lead can be tens of metres long

Hope this helps, Dave

Bradfield

Dave_C wrote: »

If you are trying to connect between phone socket and router using one of these:

Then you are doing it wrong. These cables are to connect telephones and faxes. The reason some work and some dont is that there is no standard of connectivity at theRJ11 end. They are not made to be replaced - you should not be able to unplug the lead at the telephone end. So saying, the rules may have changed since I left the telephone design industry.

Plug an ADSL filter

into the phone socket (preferably the master socket) then connect the filter to the router using an RJ-11 to RJ-11 modem lead.

The phone goes into the other socket on the filter.

Finally connect to your PC from the router using an Ethernet patch lead


Ideally, the connection to your router should be as short as possible, no more than 2 metres. The Ethernet patch lead can be tens of metres long

Hope this helps, Dave

Thanks Dave, that is very helpful. Yesterday I bought a new cable which was supposed to be an ADSL cable but I found that it doesnt work. It is the same one as in the first image you have posted. I thought it was strange it did not work as it was a brand name and new. I suppose it was intended for a phone/fax, as you have said.

Brilliant description you have posted. I am going to print that off. Thanks.