Ground wires of parallel port

[Elektor]

hi everybody?
can anyone tell me why parallel port has 8 ground wires ie 18 to 25?is one ground is not sufficient?
its urgent.
Elektor

 

[Exo]

In high quality parallel cables, each of the databit wires is shielded, 8 ground connections eases this, now each shield has a pin to be connected to, in stead of soldering 8 shield's to 1 pin (that would be messy)...

 

[danielsmusic]

the parralel port does'nt have 8 ground wires
just the shield wire is the ground.
the 8 "ground" wires are data wires to the computer.

 

[Exo]

the parallel port DOES have 8 ground wires

Look it up, pins 18 - 25 are all ground...
The data wire's you are talking about are pins 2 - 9

 

[danielsmusic]

im on about 18 to 25 are ground pins yes but the computer reads from them.
the un insulated wire is the ground you use if you dont want the computer to read from it

 

[Exo]

The computer doesnt read from them, they are GROUND pins, all connected together...and connected to the pc's case normally

You really only need to connect 1 of them, but there are 8 to allow shielding of each of the 8 databits (pins 2 - 9)...

**broken link removed**

 

[danielsmusic]

well all i can say is this (no disrispect)

i created a program in c++ that reads from all pins i put a logic level through pin 20 and it showed up i think those pins are seperate ground pins for each data wire

 

[mstechca]

pins 18-25 ARE ground pins and should all be connected together.
Without connecting the ground pins to proper ground, the parallel port device you are making won't work well.

 

[danielsmusic]

im sure they have a use otherwise they would'nt be there.

 

[Exo]

I believe this is a case to say 'oh my god :roll: '

well, whatever you say doc, i'm not going to argue...

(last tip, as i said above ,measure them, they are all connected together, what conclusion do you get out of that ? - also try measuring between your pc's case and eighter of pins 18 -25 , also connected together)