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.