RS232 Shielding connection on NI PCI card

[KNrdstrm]

Wound like to attach shield or Drain wire with at 68-pin connection at a NI 777642-08 8 port RS232 card.
Doesn't seem to have a place to connect, Can/should go to connector backshell?, etc.

[JDesRosier]

Hello,

Below is a link to the product manual for the NI 777642-08 PCI serial device. See page 6 of the pdf file.

Product Manual (NI 777642-08)

This device should include an adapter cable that connects to the SCSI 68-pin connector on the device and terminates in eight standard DB-9 male connectors.

I have never heard of a drain wire. Can you give me a more detailed description of this wire and your desired functionality? Are you disconnecting the adapter cable and trying to attach the drain wire to the 68-pin connection on the card itself? Please send me some further information, and I'll do my best to help you resolve your problem.

Best Regards,

Joe Des Rosier
National Instru
ments

[Chris_Rake]

I'm guessing drain wire = shield. The shiled of the DB-9 connector of the 68-pin breakout cable is connected to the shield of the 68 pin connector of the PCI card. This is in turn connected to chassis ground. So for shield/drain wire purposes, connecting to the shell of the DB-9 or 68-pin connector on the breakout cable should do the trick.

[KNrdstrm]

Hi JDesRosier,

Drian wire is essentially a shield, we are not using the 68 pn to 9 Dub breakout cable assy. Wondering what pin of 68 pin to connect drain (shield) to or to its backshell.

Kurt Nordstrom, EE
General Dynamics,
(952) 956-5274 (w)

[KNrdstrm]

Chris,

Correct in that Drain wire=shield, not using 68 pin to 9 pin Dsub breakout cable assy but going out from 68 pin directly. Looks like you are saying to connect shield/drain to 68 pin connector backshell, no chassis pin?

Tx
Kurt Nordstrom, EE

[JDesRosier]

Kurt,

Your easiest solution is to connect the drain wire to the backshell. This should work fine.

The other option is to probe the pins of the 68-pin connector with a DMM to find the drain pin. I looked through our product manuals, and I could not tell which pin is the drain from the pinout diagrams.

Please let me know if this works.

Good luck!

Joe Des Rosier
National Instruments