SHDSL back to back basics

Unanswered Question
Nov 16th, 2009
User Badges:

I'm struggling with the documentation.More exactly with layer 1.

Material: c1841 with HWIC-4HSDSL.

A cable is delivered from RJ45 to 2x RJ11

In the documentation I find for the cabling:

2wire, 4 wire and 8 wire + some cabling schemes. Eg


I think the delivered cable is a RJ-45 Connector to Four Standard RJ-11 Connector. But why do I have 2 RJ11 connectors?

So how do I start?

1) check the number of wires on the phone cable?


I found also that for this HWIC you've two possibilities:

Standard RJ-45 Connector to Four Standard RJ-11 Connectors or Standard RJ-45 Connector to Two Standard RJ-11 Connectors .

I know... I'm confused.


controller SHDSL 0/0/0

termination cpe

dsl-group 0 pairs 0, 1 (! what about the layer1 for choosing a combination of 0,1,2,3)

shdsl 4-wire mode enhanced

shdsl annex F-G coding 32-TCPAM

shdsl rate 1536

-> configuration for a 4 wire connector I suppose as you've two pairs.

interface ATM0/0/1

no ip address

no atm ilmi-keepalive


interface ATM0/0/1.1 point-to-point

ip add x.x.x.x x.x.x.x

logging event subif-link-status

atm route-bridged ip

pvc 0/32


So I want first to start with the layer 1 gaps.

Then I also want to use bridging if possible.

Thanks in advance

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4 (1 ratings)
paolo bevilacqua Mon, 11/16/2009 - 13:58
User Badges:
  • Super Gold, 25000 points or more
  • Hall of Fame,

    Founding Member

Wires... adjust as you like. It doesn't make a difference as long you respect pairing.

Recommend do not use bridging for best performance, scalability and troubleshooting.

Rik19972000 Mon, 11/16/2009 - 14:26
User Badges:

Why 2 RJ11 connectors?

So first I've to check how many wires my phone cable has?

If for example my phone cable has 4 wires.

dsl-group 0 pairs 0, 1


dsl-group 0 pairs 2,3

If you have a clean installation then you can chose as long you use same pairs 0,1 or 2,3 on both sides? That probably the reason that there are 2x RJ11 cables?

Like this:

Why should you work like this:

Am I right that with this one you can configure 1 router as CO and 4 routers as CPE via a 2 wire connection?

or this:

Standard RJ-45 Connector to Two Standard RJ-11 Connectors

I think this will be the cable that's delivered with the HWIC?

paolo bevilacqua Mon, 11/16/2009 - 14:30
User Badges:
  • Super Gold, 25000 points or more
  • Hall of Fame,

    Founding Member

Why? Because Cisco thought that would help someone. If it doesn't help you, crimp your own cable.

As mentioned above, you can arrange physical wiring as you like, only respect pairing.

Everything indicated in manuals and diagrams is correct until proven wrong.

Rik19972000 Mon, 11/16/2009 - 23:34
User Badges:

So on one side I can use for examples pairs 0,1 and on the other side 2,3?

What about 2,4,8 wires?

For example 8 wires, in a phone cable? 2xRJ11 coupled?

paolo bevilacqua Tue, 11/17/2009 - 05:27
User Badges:
  • Super Gold, 25000 points or more
  • Hall of Fame,

    Founding Member

No, as said above you must respect pairing.

Then you can use any cable as you like as long (again) pairing is respected.

rc5295509 Fri, 03/25/2011 - 07:00
User Badges:


Question:  You have signal in both circuit, 0 and 1 with the card HWIC-4HSDSL? because aI use a rourer 1921 with the same card and oly up one circuit? the 0 and connect this rj11 to DSLAM and only up one circuit.



This Discussion