Connecting 1-Wire devices to a RJ-11 Socket

Pinout of the RJ-11

Pinout of the 1-Wire plug
that connects to the socket
on a TINI E20 Revision C board,
or a 9097U adapter.
RJ-11 Pin Signal Name
1 VCC (5 volts regulated)
2 Power Ground
3 One Wire Data
4 One Wire Ground
5 No Connect
6 V+ (unregulated DC)


Click here for the Dallas Specification in PDF format.
Note: Colors do not match. Read below for why.

Notes:
1) A true RJ-11 wire has 4 wires (and RJ-12 has 6 wires). However, some telephone cables only have 2 wires. In that case they are usually pins 3 and 4 as shown above, and therefore suitable for 1-Wire applications.

2) One end of a telephone wire should look as above, the other end will probably not have the colors in the same order. This depends on how the plug was attached. The colors will be in the same order if the cable was constructed as shown.


It is likely that the plugs are not attached as shown. The reason for this is not clear. One reason could be that wall plugs are wired one way, say numbered left to right, and telephone equipment is wired the other way, right to left. Another reason could be that most telephone cables are used as extension cables and thus are used with couplers. However, couplers may or may not reverse the wires, so when connected to a cable that is reversed and a coupler that is reversed, the result is to create a non-reversed cable.
Apparently telephones don't really care, since both kinds of cables and both kind of couplers can be found, but the 1-wire devices do!

Use only telephone cables which have both modular plug connected in the same wire order -- the same as above for each end. And avoid couplers. (Of course, the actual colors do not matter, but the order does.)


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