RJ11 TO RJ45?

Hi,

My ADSL filter has an RJ11 output, but my Netgear router has an RJ45
input for its internet connection. I ordered an RJ11/RJ45 adaptor but
the company sent me the wrong thing (an RJ45 to RJ45 straight through
coupler!). Does anyone know if I can make the connection without an
adaptor? I have tried an ethernet cross-over cable and it doesn't work
(i.e. from the filter RJ11, I use an RJ11 cable, then the RJ45/RJ45
straight through coupler, then the ethernet cross-over cable then into
the router's RJ45 internet input). I have also tried with an ordinary
ethernet cable (i.e. not a cross-over one), and that doesn't work
either.

Any other suggestions, or do I have to get an RJ11/RJ45 adaptor to be
able to connect?

Thanks,

Mark.

Mark, Devon wrote:
> Hi,
>
> My ADSL filter has an RJ11 output, but my Netgear router has an RJ45
> input for its internet connection. I ordered an RJ11/RJ45 adaptor
> but
> the company sent me the wrong thing (an RJ45 to RJ45 straight
> through
> coupler!). Does anyone know if I can make the connection without an
> adaptor? I have tried an ethernet cross-over cable and it doesn't
> work
> (i.e. from the filter RJ11, I use an RJ11 cable, then the RJ45/RJ45
> straight through coupler, then the ethernet cross-over cable then
> into
> the router's RJ45 internet input). I have also tried with an
> ordinary
> ethernet cable (i.e. not a cross-over one), and that doesn't work
> either.
>
> Any other suggestions, or do I have to get an RJ11/RJ45 adaptor to
> be
> able to connect?
>
> Thanks,
>
> Mark.

Have you got a cable router and not an adsl router by any chance?

If so what you want to do will not work. All ADSL routers will have a
rj11 port.

kráftéé wrote:
> Mark, Devon wrote:
> > Hi,
> >
> > My ADSL filter has an RJ11 output, but my Netgear router has an RJ45
> > input for its internet connection. I ordered an RJ11/RJ45 adaptor
> > but
> > the company sent me the wrong thing (an RJ45 to RJ45 straight
> > through
> > coupler!). Does anyone know if I can make the connection without an
> > adaptor? I have tried an ethernet cross-over cable and it doesn't
> > work
> > (i.e. from the filter RJ11, I use an RJ11 cable, then the RJ45/RJ45
> > straight through coupler, then the ethernet cross-over cable then
> > into
> > the router's RJ45 internet input). I have also tried with an
> > ordinary
> > ethernet cable (i.e. not a cross-over one), and that doesn't work
> > either.
> >
> > Any other suggestions, or do I have to get an RJ11/RJ45 adaptor to
> > be
> > able to connect?
> >
> > Thanks,
> >
> > Mark.
>
> Have you got a cable router and not an adsl router by any chance?
>
> If so what you want to do will not work. All ADSL routers will have a
> rj11 port.

Thank you...and the more I look into this the more I see that you're
absolutely...right! The word 'bugger' seems quite appropriate at this
moment in time!

"kráftéé" <kraftee@b&e-cottee.me.uk> wrote in message
news:enol34$aec$(E-Mail Removed)

[snip]

> Have you got a cable router and not an adsl router by any
> chance?
> If so what you want to do will not work. All ADSL
> routers will have a rj11 port.

Technically, an ADSL modem/router will have an RJ11 port. A router on its
own may or may not contain a modem, hence the confusion..!

Actually, not *all* ADSL modem/router devices have an RJ11 port for the
phone line connection. My AVM Fritz!Box Fon has an RJ45 connectors for the
phone line, they supply the relevant cable.

There is also a second RJ45 for connection to the normal voice side of the
filter, this is for use with the built in VoIP ATA so that calls can be
made/received over the PSTN rather than VoIP if required. Again the cable
supplied has to be used, as both are wired non-standard.

Ivor

>
> Actually, not *all* ADSL modem/router devices have an RJ11 port for the
> phone line connection. My AVM Fritz!Box Fon has an RJ45 connectors for the
> phone line, they supply the relevant cable.
>

And an RJ11 plug will fit into an RJ45 connector. It's designed that way.

If the phone line is on the centre 2 pins ( 4+5 of the RJ45 ) which it
usually is, then no adapter is required. ( Ever wonder why networking used
pins 1+2, 3+6 ? There's the answer. Because you can carry analog telephony
over 4+5 on the same cable. One outlet, plug in either a computer with an
RJ45 cord, or a phone with an RJ11 cord. )

Often, you can just plug the RJ11 cable into the RJ45 port.
( assuming no non-standard wiring. )

--
Ron

"Ron Lowe" <ronATlowe-famlyDOTmeDOTukSPURIOUS> wrote in
message news:45a006d6$0$757$(E-Mail Removed)
> > Actually, not *all* ADSL modem/router devices have an
> > RJ11 port for the phone line connection. My AVM
> > Fritz!Box Fon has an RJ45 connectors for the phone
> > line, they supply the relevant cable.
>
> And an RJ11 plug will fit into an RJ45 connector. It's
> designed that way.

Assuming your next sentence is true.

> If the phone line is on the centre 2 pins ( 4+5 of the
> RJ45 ) which it usually is, then no adapter is required.

It may not be, though. To be honest, I don't know if it is or not, but I
do know that the voice connection to the PSTN is on pins 1 and 8, so you
*have* to use the supplied cable for that..!

> ( Ever wonder why networking used pins 1+2, 3+6 ? There's the answer.
> Because you can carry analog
> telephony over 4+5 on the same cable. One outlet, plug
> in either a computer with an RJ45 cord, or a phone with
> an RJ11 cord. )
> Often, you can just plug the RJ11 cable into the RJ45
> port. ( assuming no non-standard wiring. )

But no non-standard wiring cannot be assumed.

Ivor

Ron Lowe <ronATlowe-famlyDOTmeDOTukSPURIOUS> wrote:
>> Actually, not *all* ADSL modem/router devices have an RJ11 port for
>> the phone line connection. My AVM Fritz!Box Fon has an RJ45
>> connectors for the phone line, they supply the relevant cable.
>>
>
> And an RJ11 plug will fit into an RJ45 connector. It's designed that
> way.

Yebbut, it will damage the RJ45 socket. Try plugging a RJ11 plug into a RJ45
socket and observe how the outer wires are pushed much further by the edge
of the plug. After a few times it won't work properly anymore with a RJ45
plug.

--

Geoff

GeoffC wrote in message
45a2293c$0$64090$(E-Mail Removed):

> Ron Lowe <ronATlowe-famlyDOTmeDOTukSPURIOUS> wrote:
>>> Actually, not *all* ADSL modem/router devices have an RJ11 port for
>>> the phone line connection. My AVM Fritz!Box Fon has an RJ45
>>> connectors for the phone line, they supply the relevant cable.
>>>
>>
>> And an RJ11 plug will fit into an RJ45 connector. It's designed that
>> way.
>
> Yebbut, it will damage the RJ45 socket. Try plugging a RJ11 plug into
> a RJ45 socket and observe how the outer wires are pushed much further
> by the edge of the plug. After a few times it won't work properly
> anymore with a RJ45 plug.

I didn't know that an RJ11 was actually designed to fit into an RJ45
socket - I thought it was just a happy/unhappy accident. If the plug pushes
the outer contacts aside, then it sounds as it it's not *designed* to fit.

It's a shame that RJ11 plugs fit into RJ45 sockets, because it's very easy
for a novice to plug the dial-up modem lead into the network socket by
mistake - I've even done it mysef, once, absent-mindedly. The symptom is
that the phone line gets shorted out, giving no dialling tone and no click
if you lift the handset of a phone. Fortunately it's not a permanent fault:
if you remove the modem lead and then jiggle the phone on its cradle, the
dialling tone returns after a moment or two. I wonder if a shorted line
triggers a "pillock" alarm in the exchange!

On 8 Jan 2007, "Martin Underwood" <a@b> wrote:

>I didn't know that an RJ11 was actually designed to fit into an RJ45
>socket - I thought it was just a happy/unhappy accident.

Yes, it is, apparently.


>It's a shame that RJ11 plugs fit into RJ45 sockets, because it's very easy
>for a novice to plug the dial-up modem lead into the network socket by
>mistake - I've even done it mysef, once, absent-mindedly.

It is easy to do, especially if someone is on the phone and seems to have
zero interest in getting the right cables in the right sockets. I tend
to go very slowly, normally having a similar modem/router here to use
to check they are plugging/unplugging the right cable. In some ways
it would have been better to use a different style socket.

NoNeedToKnow wrote in message
(E-Mail Removed):

> On 8 Jan 2007, "Martin Underwood" <a@b> wrote:
>
>> I didn't know that an RJ11 was actually designed to fit into an RJ45
>> socket - I thought it was just a happy/unhappy accident.
>
> Yes, it is, apparently.
>
>
>> It's a shame that RJ11 plugs fit into RJ45 sockets, because it's
>> very easy for a novice to plug the dial-up modem lead into the
>> network socket by mistake - I've even done it mysef, once,
>> absent-mindedly.
>
> It is easy to do, especially if someone is on the phone and seems to
> have zero interest in getting the right cables in the right sockets.
> I tend to go very slowly, normally having a similar modem/router here
> to use
> to check they are plugging/unplugging the right cable. In some ways
> it would have been better to use a different style socket.

Of course it would have been better to use a different style socket. The
first rule of sockets is that incompatible sources (eg phone line versus
Ethernet) should not use plugs/sockets that can accidentally be plugged in.
There's no sin in making things as idiot-proof as possible.

On a PC with Ethernet on the motherboard and a PCI modem, it's difficult to
get it wrong. But on a PC with a modem and a PCI Ethernet card right next to
each other, its very easy to plug the phone lead into the wrong card,
especially if you are fumbling round the back of the PC because the
keyboard, mouse or USB leads aren't long enough to pull the PC right out
with the leads still connected, so you can see (rtaher than just feel) what
you are doing.

Which can first - the RJ11 or the RJ45? Probably the RJ11 because it's been
the US phone socket for ages. Ethernet using twisted pair on RJ45 (as
opposed to a D connector for thick Ethernet or a BNC for thin Ethernet)
probably came quite a bit later.

(Does anyone remember the "joys" of thin Ethernet, trying to locate
whereabouts on a long cable run the short or open circuit lies, and the
problem of unplugging a PC from the network and taking the whole network
down? Twisted pair may use far more cable than a daisy-chain arrangement,
but it's far more resilient to faults.)