Long vga cable with STP
Written by Walter on x/x/2004
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 4. 5. 6. Red - (aka GND) Orange stripe 7. Green - (GND) Green stripe 8. Blue - (GND) Blue stripe 9. 10. Ground (GND) shield wire. 11. 12. 13. H sync Brown 14. V sync Brown stripe 15.
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:
- Thinner form factor.
- Cheaper cable. Plenum being much cheaper
- 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.
- similarly, no break-out BNC to HD-15 cables required. These bring their own problems