The female connector is on the cable of a remote keypad device. The original keypad device was "powered" from a pair of the RS-232 "handshake" lines. The keypad manufacturer changed from a red LED to a blue LED (everyone knows that blue is better). Unfortunately, our device RS-232 drivers won't supply enough power to run the keypad with the blue LED. The jumper adds our system +5V to the handshake lines to power the keypad. We can modify our production units to perform the necessary shorting function, but there are a batch of our devices in the field that are planned to upgrade to the new keypad device. If the shorting jumper were to fall out of the keypad female DB-9 connector, the remote keypad wouldn't work. In my sample-of-one prototype, the barbs of the folded back ends of the guitar string wires hold the shorting jumper in place so well that the shape of the wire is destroyed by trying to pull the shorting jumper out with needle nose pliers. Thanks, Carl Carl Van Wormer, P.E. Senior Hardware Engineer Cipher Systems 1800 NW 169th Place, Suite B-100 Beaverton, OR 97006 This message may contain confidential and/or proprietary information, and is intended for the person/entity to whom it was originally addressed. Any use by others is strictly prohibited. If I sent this to you by mistake, please be nice and delete it, then tell me of my mistake so I can send it to the right person. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Upton, Shawn Sent: Wednesday, August 19, 2009 8:48 AM To: [log in to unmask] Subject: Re: [TN] Guitar string shorting jumper What will fail if the U piece falls out? Will the resulting cost of resolving that issue(s) offset the cost of buying (50) new custom molded connectors? Why cannot the jumper be applied elsewhere in the system? Lastly, why not a "dongle" which would be just two back-to-back connectors, with the required jumper in place? I can see the need to reduce waste (cost) and to make it not require yet another item--but it seems like a failure point that might be worse of a headache in the field if it ever occurred, than if the solution was applied elsewhere. Shawn Upton, KB1CKT Test Engineer Allegro MicroSystems, Inc [log in to unmask] 603.626.2429/fax: 603.641.5336 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Carl VanWormer Sent: Wednesday, August 19, 2009 11:38 AM To: [log in to unmask] Subject: [TN] Guitar string shorting jumper We have need to "permanently" connect two adjacent pins of a female DB-9 connector that has a molded housing, so we can't get at the back side of the connector for a properly soldered connection. The first suggestion was an adapter (male and female connectors, PC board, and insulating housing or heat-shrink cover). For the planned quantity of 50 units, this design effort seemed like a bit of overkill, even ignoring the size of the ugly protrusion of this adapter out the back of the product. An alternative is being considered that needs some "fatherly guidance" from the collective TechNet intelligence: A short length of .008" steel wire guitar string with a U-bend to span the two female terminals could be inserted into the proper terminals of the female DB-9 connector. If the two legs were bent back on themselves, forming barbs, the shorting jumper could be inserted into the DB-9, with the barbs performing a lock-in function to hold the shorting jumper in place. A quick test of a bent-up sample indicates that this approach seems to work well, with only minimal distortion of the female sockets. The final product is expected to have only a few insertion/removal cycles in its lifetime. The questions to this group are: 1. How crazy am I to suggest this solution? 2. Should I consider Gold plating (or something else) to increase reliability? Thanks, Carl --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------