ribbon cable for a 4P4C connector ?

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cosmicray
Posts: 48
Joined: Tue Aug 19, 2014 7:09 am
Location: north Florida

ribbon cable for a 4P4C connector ?

Post by cosmicray » Sat Dec 13, 2014 4:21 pm

I have a bag of 4P4C connectors, and I need to crimp a few of them onto a length of ribbon cable.

I have two kinds of ribbon cable in front of me, one is a 6-conductor/15-foot piece that I purchased from Sparkfun. The other is a 100-foot roll of very old (circa 1973) 25-conductor ribbon cable. The old stuff appears to have the correct spacing to insert into the 4P4C (caliper suggests 4+mm) while the newer cable measures 5.5mm for 4-conductors. The old cable is so old the insulation is brittle & cracking (but it's the correct spacing). The old ribbon cable measures 25mm across 25 conductors, while the new stuff looks like 8mm across 6 conductors. So I guess I need 4mm for 4 conductors (or something with that spacing that I can cut down).

Is this readily available in 2014 ?
First learned EE at the juncture of vacuum tubes and solid state, Still learning.

Dave Mueller
Posts: 198
Joined: Sat Apr 30, 2011 8:09 pm

Re: ribbon cable for a 4P4C connector ?

Post by Dave Mueller » Sat Dec 13, 2014 5:04 pm

Yes, almost every hard wired telephone uses ribbon cable. Go to the nearest electronics/home improvement store and look for a phone extension cord. Make sure it has all 4 conductors (red green black yellow).

cosmicray
Posts: 48
Joined: Tue Aug 19, 2014 7:09 am
Location: north Florida

Re: ribbon cable for a 4P4C connector ?

Post by cosmicray » Sat Dec 13, 2014 6:24 pm

The 4P4C connector is the one used between the telephone and the handset. The telephone to the wall is a 6P4C (or RJ-11). Pretty much all of the handset cables I have ever seen are coiled. I need a flat ribbon, not a coiled cable. Although it may be that the cable used in the 6P4C is the same pitch I need.

I found a technical drawing that shows the pitch on the 4P4C connector to be 1.02mm (0.040 inch). That explains why the ~1.0mm pitch (ancient) cable looks so close. The smallest I've located thus far, is some new/old stock 3M cable at 1.08mm. Still looking.
First learned EE at the juncture of vacuum tubes and solid state, Still learning.

Mee_n_Mac
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Re: ribbon cable for a 4P4C connector ?

Post by Mee_n_Mac » Sat Dec 13, 2014 8:46 pm

How long must it be ? For the few pennies extra, you might buy one w/connectors and snip one end off and recrimp to get a custom length or pinout.
http://www.homedepot.com/p/Steren-25-ft ... /205317853

cosmicray
Posts: 48
Joined: Tue Aug 19, 2014 7:09 am
Location: north Florida

Re: ribbon cable for a 4P4C connector ?

Post by cosmicray » Sun Dec 14, 2014 8:05 am

Mee_n_Mac wrote:How long must it be ? For the few pennies extra, you might buy one w/connectors and snip one end off and recrimp to get a custom length or pinout.
http://www.homedepot.com/p/Steren-25-ft ... /205317853
That is effectively what I did last night. In my wire box, I found a 15-ft length with RJ11 on both ends, snipped off one end, and used a about a foot of that. That worked. But the wire used in modular telephone cables is different from the wire used in ribbon cables. The difference is not merely the gauge, but there is something in the wire strands (looks like a thin vinyl strand) that is there to assist in the constant flexing that the average ribbon cable could not deal with.

The wire type I need would not have to flex as either telephone cord might, but only rarely (like a ribbon cable). I am going to give this a try, but I have no clue what the current carrying ability of that wire type might be. I *think* I need to carry 50 mA, with an occasional peak of 100 mA (best guess at this point). I am thinking that 10-12 inches is the length needed.

Looking some more on eBay (and trying different search terms), I found a few sellers who offer 1.0 mm pitch ribbon cable. This is very likely to be something that was designed for board-to-board jumpers, where many parallel signals were needed in a confined space. If the telephone cord does not work out, I may have to try one of those.
First learned EE at the juncture of vacuum tubes and solid state, Still learning.

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