The standard telephone connector. A tab snaps into the wall socket and has to be pressed to be removed. RJ-11 connectors can house up to four wires.

So I got my DS9097U-009 a week ago. The 9097U is an adapter converting serial port data to Dallas Semiconductor's one-wire LAN, allowing temperature sensors (DS1820) and other good stuff to be connected to a computer.

In the rear of the adapter is an RJ-11 connector using the two center pins to connect to the one-wire network. All right, I thought when I ordered it, I'll just crimp an RJ-11 head to a cable and be started. Silly me - knowing perfectly well that RJ-11 is not that standard Ethernet plug with eight conductors, yet not understanding the full implication of that: I neither have a crimp tool nor any RJ-11 heads.

Two days ago I bought some connectors anyway and I figured they could probably be crimped to the cable without the proper tools:

I inserted the cable in the head placing the individual wires at their proper locations. Using a flat screw driver I pressed each prong into its wire. It was hard not to slip and push the screw driver through the plastic casing and I still have red aching marks in my palm from the screw driver.

The cable works fairly good and seems to be reliable, though.

There seems to be some confusion out there about how many wires an RJ-11 holds. My experience can be described thusly: The female connector in the adapter (named RJ-11 by the product specification) had six wires. The plug I purchased (RJ-11 according to Scandinavian elecronics store Elfa) had space enough for six conductors, but had only four pieces of metal in front and only four wires would fit in it.

Crimping your own RJ-11 telephone cord

This is relatively easy, compared to Ethernet's RJ-45 T568A/T568B layouts. BUT there is a twist, you must flip the RJ11 connector on one end so that same-coloured wires line up when when the cables crimps are put end-to-end. The Black and Yellow wires are optional and may not be present.

     ________________      ________________
    |                |    |                | 
----|-##---|=Black===| T2 |===Black=|---##-|----
    | ##   |=Red=====| R1 |=====Red=|   ## |
    | ##   |=Green===| T1 |===Green=|   ## | 
----|-##---|=Yellow==| R2 |==Yellow=|---##-|----
    |________________|    |________________|
     Viewed connector side, clip facing away

Using Cat-5 cable to make telephone cords

The key here is consistency. If all your cables, keystone connectors, hubs and patch panels conform to T568A/T568B standards, then you can go ahead and use the Blue and Brown pairs, as they're not used by Ethernet 10/100 baseT. Note that the Cat5 will be somewhat difficult to fit in an RJ-11 end, and you must clip off and discard Ethernet's Orange and Green twisted pairs. Again, pair #2 aka Brown is optional.

     ________________      ________________
    |                |    |                | 
----|-##---|=w/Brown=| T2 |=w/Brown=|---##-|----
    | ##   |=Blue====| R1 |====Blue=|   ## |
    | ##   |=w/Blue==| T1 |==w/Blue=|   ## | 
----|-##---|=Brown===| R2 |===Brown=|---##-|----
    |________________|    |________________|
     Viewed connector side, clip facing away

The full wiring details can be found here, crimping techniques there.