Can I plug an ADSL cable to a router with an RJ11 to RJ45 converter?

Question

I have an ADSL router that connects to the ISP with PPPoE on its WAN through a cable that has an RJ11 plug. I would like to use my main router that also has PPPoE on its WAN, but only has RJ45 plugs.

Can I use an RJ11 to RJ45 converter to plug the cable from the ISP into my router and "login" through its PPPoE? Is there something else that my router should know? Does the (not so high quality) ISP provided router has something special? If my router is inadequate can I still do this with the proper router?

Answer 1

The short answer: Probably not.

ADSL is one way to transfer data on simple copper wires - most often telephone lines. The RJ11 is commonly used for devices that "understand" telephone lines.

The RJ45 plug is used for Ethernet (TCP/IP and similar standards) and IP telephone interconnections, and here you have a completely different method of transferring the data.

You will not be able to interconnect these with simple copper wires only - so this is comparable to "Hardware".

PPPoE - i.e. Point to Point Protocol over Ethernet is a method to "connect" digitally, it has no provision for the physical interconnection and the related signalling - so here you have "Software".

Answer 2

You will not be able to do this, because your RJ45 router does not have an ADSL modem to modulate the signal. Your router is expecting to receive Ethernet frames. Typical DSL, in the US, is fed ATM from the telco DSLAM to your router, this has a PVC (or vpi/vci) and is a completely different encapsulation than ethernet. So your router would likely drop all frames because they don't adhere to the standards.

The short of it is, your telco is speking french, and your router only understands spanish.

One option, as you mentioned in the comment, is to bridge the telco modem so it is a layer 2 pass through. It is, essentially, converting ADSL into Ethernet and feeding that to your router. The benefit of this, is the PPPoE COULD be handled on your RJ45 router, and the public address will also live on your RJ45 router. If YOUR router is a Cisco IOS router, you create a Dialer and put the physical interface in a pppoe pool. The dialer is configured with pap/chap, and obtains your public negotiated address.

Another option, is to buy a router with a DSL modem embedded. Since this would likely cost more, I mention it as a second option. An example of this is any Cisco 800 series thats last digit ends in a 7. (E.g. 857, 877, 887 etc)