but you can get six conducter cable with the six pin RJ12 jacks on 
it...they're not twisted pair, so if you have a need for six pin control 
jacks and six conducter control cable, you don't need to use cat5 or 8 
conducter cable.
If you have a need for 8 conducter cable using RJ45 8 pin jacks, like for a 
microphone or something, then the twisted pairs in the cat5 aren't going to 
alter anything very much.  Twisted pairs become relevant when used for high 
speed data transfer, or telephone applications where impedance must be 
continuous down the cable.  For the tiny amount of signal passing through a 
mike extention cable, it would have absolutely no effect weather you were 
using part of a twisted pair or not for audio or PTT or up/down or fantom 
power or whatever.
It's a totally different relm than networking or telecommunications, so the 
specifics of the cable are pretty much a moot point beyond how many actual 
conducters they contain.
But you are right, one must insure that the pin outs match up at either 
end...and using a standard ether net cable, cat5, with RJ45's on each end 
will insure that you have a straight through pin to pin connection.
With the kenwood radios, both the control cable, and the mike extension 
cable are straight through.  So, if you have cable that has pin to pin 
connection, like pin 1 on one end connects to pin 8 on the other end and so 
on, it'll work.
If you have a cable that goes pin 1 to pin 1 and so on, it's not a straight 
through cable and will not work.

73
Colin, V A6BS
----- Original Message ----- 
From: "T. Joseph Carter" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, September 03, 2011 6:04 AM
Subject: Re: TM-V71A question


> You're likely to get mixed results using standard network cables on
> something using six conductors even if the RJ-45 connectors fit.  The
> reason why should be obvious to a ham: Inside the cat-5 cable are
> twisted pairs which provide balanced transmission lines for the 8
> conductors (actually only 4 of them got used until the era of
> gigabit ethernet, but that's another story!)  In order to be able to
> use cat-5 to control any radio not wired for 8 conductor ethernet
> cables, you're going to need to connect the pairs appropriately.
>
> If ethernet has wire pairs A, B, C, and D, with wire 1 being striped
> and wire 2 being solid, you get wiring like this:
>
> 1: A1
> 2: A2
> 3: B1
> 4: C2
> 5: C1
> 6: B2
> 7: D1
> 8: D2
>
> Electrically, it doesn't matter which pair is which, or which wire is
> solid or striped so long as you match the wires on both ends with
> your continuity tester!  But there is a color standard, which we'll
> ignore for the sake of argument.  Pairs C and D are completely unused
> by 100Mbit ethernet, so you occasionally see power lines run that
> way, but I wouldn't suggest it on gigabit lines!  *grin*
>
> Probably something using six conductors will take an RJ-45 connector,
> but will tend to only use the middle six contacts.  It's easy to see
> then that whatever signal happens to be passed on lines 2 and 7,
> using a regular ethernet cable, would be unbalanced.
>
> Two likely possible wirings:
>
> 1: NC
> 2: A1
> 3: A2
> 4: B1
> 5: B2
> 6: C1
> 7: C2
> 8: NC
>
> or more likely perhaps:
>
> 1: NC
> 2: A2
> 3: B1
> 4: C2
> 5: C1
> 6: B2
> 7: A1
> 8: NC
>
> This is assuming straight connection.  Don't assume that!  Somewhere
> I had a brilliant little old-school phone wall plate that broke out
> an RJ-45 connector to 8 screw terminals.  Today, you'll find people
> mostly use keystone jacks and a punchdown tool, simply because doing
> so untwists very little wire, which helps avoid unbalancing your
> balanced lines!  Remember, we're talking at least 100Mbit/sec here,
> which means those twisted pairs are carrying VHF signals.  Moreover,
> the signals are bidirectional!
>
> If you can find out your radio's control head pinout, it'd be much
> easier to wire a cable's pairs appropriately.  You'd be surprised how
> well a twisted pair of wires eliminates the need for a shield if you
> have the right signals running in the right pairs.  If not, shielded
> twisted pair does exist for industrial environments.
>
> Joseph
>
>
> On Fri, Sep 02, 2011 at 10:19:50PM -0500, Gary Smith wrote:
>>Thanks to everyone who responded to my questions.  I'm not ready to put 
>>one
>>in a vehicle yet but this info will help when I am.
>>
>>73, Gary-N5GD
>>
>>
>>-----Original Message-----
>>From: For blind ham radio operators [mailto:[log in to unmask]]
>>On Behalf Of colin McDonald
>>Sent: Friday, September 02, 2011 12:50 PM
>>To: [log in to unmask]
>>Subject: Re: TM-V71A question
>>
>>well if the control head cable is 6 pin, then you can't use cat5 because
>>cat5 is 8 conducter, and RJ45's are 8 pin.
>>You have to use that flat telephone or network type cable with 6 
>>conducter,
>>and the RJ12 six pin jack...which is the same size as the RJ45, but only 
>>has
>>
>>six pins instead of 8 on the plug.
>>I would imagine you can probably find shielded 6 conducter cable though 
>>just
>>
>>like you can get shielded 8 conducter which is cat6.
>>
>>73
>>Colin, V A6BS
>>----- Original Message -----
>>From: "Butch Bussen" <[log in to unmask]>
>>To: <[log in to unmask]>
>>Sent: Friday, September 02, 2011 8:53 AM
>>Subject: Re: TM-V71A question
>>
>>
>>> There have been mixed results using regular cat 5 cable.  Kenwoos uses 8
>>> pin network cables, rj 45 I think.  Kenwood's over priced cable does 
>>> have
>>> the audio shielded.  The network cable is worth a try though.  The 71 
>>> uses
>>> a rj 45 on the radio and a smaller, I think six pin on the control head.
>>> You could possibly use the short pig tail that comes with the radio and
>>> adapt to rj 45 cable.  The way Kenwood packages their stuff amazes me.
>>> They actually make two kits, one has long power cord, long mike and
>>> control cables but no mounting bracket.  Tlhe $50 one just has bracket 
>>> and
>>> control cable.  Go figure!!!
>>>
>>> 73
>>> Butch
>>> WA0VJR
>>> Node 3148
>>> Wallace, ks.