Long vga cable with STP
Written by Walter
Need this for my dad. He wants to install a long vga cable for a HTPC (longer than 15meters). First I thought it would be very expensive (since my 13meter vga cable cost a lot already).
But furtunately thanks to hackaday, we can now just use a STP (cat 5 shielded twisted pair, so similar to UTP...) cable which is a lot cheaper.
The only local place I could find shielded Cat 5 products was at Fry's. L-com has them but they are mail order and a little more expensive.
I did the exact same thing as before. I bought a 25 foot shielded cat 5 cable and cut it into a 6 foot and 19 foot piece. I also bought a shielded Cat 5 junction box, two HD-15 male solder cup plugs and to 9-pin metal hoods (HD-15 is the same size). I wired the HD-15's in the following fashion to the shielded cat 5 cable.
HD-15 pin Cat 5 color
1. Red + Orange
2. Green + Green
3. Blue + Blue
6. Red - (aka GND) Orange stripe
7. Green - (GND) Green stripe
8. Blue - (GND) Blue stripe
10. Ground (GND) shield wire.
13. H sync Brown
14. V sync Brown stripe
VGA Video connector pinouts:
Pin # - Signal Name - CAT 5 Conductor
1 - Red - Orange
2 - Green - Green
3 - Blue - Blue
4 - No Connection
5 - Ground - No Connection
6 - Ground - Orange/White
7 - Ground - Green/White
8 - Ground - Blue/White
9 - No Connection
10 - Ground - No Connection -
11 - No Connect
12 - DDC DAT - No Connection
13 - Horizontal Synchronization - Brown
14 - Vertical Synchronization - Brown White
15 - DDC Clock - No Connection
The "-" signals are actually the very same ground as "Ground" is. The H and V don't need their own separate ground line. The results were excellent as I stated before.
At this point you might be saying cool but what does shielded Cat 5 give me over bundled coax? It gives a few things:
1. Thinner form factor.
2. Cheaper cable. Plenum being much cheaper
3. Much easier to solder to an HD-15 connector. Bundled coax requires shield terminators when soldering and big mouth back shells to allow the larger diameter of the cable to exit.
4. similarly, no break-out BNC to HD-15 cables required. These bring their own problems