Wiring help?

Tim ignored_mailbox at yahoo.com.au
Tue Apr 4 16:51:32 UTC 2006


Tim:
>> I wonder if the way some cables are formed makes it easier to wire it
>> one way or another?  Hand wrangling the wires into the right place to
>> crimp on a plug can be a right pain.  You've got untangle wires, cross
>> some over others, and get them all to go into the plug the same
>> distance.  It would have been a lot easier to do that if they'd come up
>> with a wiring arrangement different from the current specs.  i.e. A pair
>> on 1 & 2, the next on 3 & 4, the next on 5 & 6, the last on 7 & 8,
>> instead of having the break apart pairs and straddle others.  I
>> seriously doubt that would have degraded noise rejection.
 

Mikkel L. Ellertson:
> It has to do with backward compatibility. Remember, the same jacks
> are used for more then Ethernet.

I've read about that, but I really do not think it's a sensible thing to
mix phone and ethernet wires together in the one connector as a standard
thing to do.

> One consideration is being able to plug an RJ-11 plug into an RJ-45
> jack. (Not really a good idea, as it can bend the outside pins of the
> jack...) The center 4 pins on a RJ-45 jack are the same as a RJ-11
> jack.

I agree, even with the little plastic spacer that you can fit around
them, they're not a good fit.

For a long time, here in Australia, those weak little RJ style plugs
were not used.  I think I only really saw them come out when modems hit
about 14k speeds.  And when we did use them, we had smaller 6 pin
connectors on phone cables compared against the larger 8 pin connectors
on ethernet.  It was quite obvious, just from looking at plugs and
sockets, which was supposed to go in where.  Now there's a trend to use
the larger 8 pin connectors on everything.  Though inconsistently, for
instance the phone usually has the small 6 pin socket on the handset
unit, but the larger 8 pin at the wall-socket end of the cable.

-- 
(Currently running FC4, occasionally trying FC5.)

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