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#176957 04/16/08 11:27 PM
Joined: Mar 2006
Posts: 15
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ctardi Offline OP
Member
Hello All,
Long time lurker, figure I should start posting again seeing as how I am trying to accomplish something unique.

I am attempting to develop a fixture for preforming programming and testing of a microcomputer. There are several ports on the computer that are positioned to allow for a testing jig to be built. I
This is similar to what I am working with, we have a version modified by the manufacturer with slightly different hardware, but you get the point.
[Linked Image from bizsyscon.com]


I have already tackled power and db9 connections. The DUT slides on two rails, so that it is pressed downwards onto the connectors. I now need to come up with a way to connect to the rj45 jack.

Does anybody know of a panel mount MALE rj45 connector? Failing that I do have access to a mill, so I may be able to make something to hold a standard RJ45 cable end in place, but I would like to come up with something a bit less mickey mouse. Unfortunately spring pins are not an option due to some of the custom hardware on the board.

I appreciate any ideas that you may be able to share with me!


Proud Inventor of the Three Phase Light Bulb!
Joined: Mar 2006
Posts: 15
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ctardi Offline OP
Member
Well...I kinda found a 'mickey mouse' solution to this. I will use a waterproof rj45 such as roughly pictured...My solidworks skills aren't the best, but you get the point. Should be able to mount it by the flange, as it is 3 pieces screwed together.

[Linked Image from ctardi.com]


Proud Inventor of the Three Phase Light Bulb!
Joined: May 2005
Posts: 247
T
Member
Pet peeve of mine: people using the wrong connector designations.

1. DB9 - The correct designation for the 9 pin D-sub connector is DE-9. The second letter designates the physical size of the connector. common sizes (with common pin counts) are DA(15), DB(25), DC(37), DD(50), and DE(9). variations on pin counts exist, including some with larger high-current or coaxial positions. source: ITT/Cannon catalog - 1969 to present. The problem is that DB-25 was a very common connector for a long time, and when the 9 pin version started coming into common usage, everybody assumed that they were also DB, not understanding what the B portion of the designator really means.

2. RJ-45 - connectors do not have RJ designations until they are wired to a particular wiring pattern as defined by the appropriate USOC (Universal Service Ordering Code). The RJ designation specifies a specific connector, wired to a specific wiring pattern, for a specific telephone service. Some connectors such as the 6 position 4 contact (6p4c), and 8 position 8 contact (8p8c) modular connectors can be wired to multiple (and incompatible) USOC specs..

For example RJ12, RJ13 and RJ14 all use the same connector, wired the same, except for the actual phone, and the equipment termination. RJ12 and RJ13 are used for 1A2 type key systems, and share the same phone wiring, but are terminated to the equipment in a different manner. RJ14 is used for 2 line POTS phones. If a phone wired for RJ12 or RJ13 is plugged into a jack wired for RJ14, the second line will be shorted when the phone goes off hook.

The networking folks love to call 8p8c connectors wired for ethernet "RJ-45", completely ignoring the fact that the USOC spec for RJ45 calls for a similar, but different connector (keyed, vs unkeyed), which is physically different from, and wired differently from ethernet. I can build a cable that fully complies with the requirements of RJ45, that will not plug into, nor have any electrical continuity with the contacts used for ethernet. It's kind of like trying to plug a 5-20P into a 6-15R, except there are more pins to choose from, and most of the time, things won't explode when you do so, although there are exceptions. (Don't plug a cable carrying a ISDN U interface into a cisco router aux port. chips tend to change from semiconductor to smoke state.)

Ethernet connectors do not have an RJ designation, despite the misuse of the RJ45 designation by the networking/computer industry.

Joined: Jul 2004
Posts: 9,662
Likes: 4
G
Member
I used to get pedantic about things like that and things like "baud" vs "bit rate" but eventually I decided that as long as everyone knows what you mean, who cares?


Greg Fretwell
Joined: May 2005
Posts: 247
T
Member
Thats great until you ask for the correct item, and are provided with the wrong item, or a blank stare..

Joined: Oct 2006
Posts: 745
E
Member
Originally Posted by techie
Pet peeve of mine: people using the wrong connector designations.

1. DB9 - The correct designation for the 9 pin D-sub connector is DE-9. The second letter designates the physical size of the connector. common sizes (with common pin counts) are DA(15), DB(25), DC(37), DD(50), and DE(9). variations on pin counts exist, including some with larger high-current or coaxial positions. source: ITT/Cannon catalog - 1969 to present. The problem is that DB-25 was a very common connector for a long time, and when the 9 pin version started coming into common usage, everybody assumed that they were also DB, not understanding what the B portion of the designator really means.

2. RJ-45 - connectors do not have RJ designations until they are wired to a particular wiring pattern as defined by the appropriate USOC (Universal Service Ordering Code). The RJ designation specifies a specific connector, wired to a specific wiring pattern, for a specific telephone service. Some connectors such as the 6 position 4 contact (6p4c), and 8 position 8 contact (8p8c) modular connectors can be wired to multiple (and incompatible) USOC specs..

For example RJ12, RJ13 and RJ14 all use the same connector, wired the same, except for the actual phone, and the equipment termination. RJ12 and RJ13 are used for 1A2 type key systems, and share the same phone wiring, but are terminated to the equipment in a different manner. RJ14 is used for 2 line POTS phones. If a phone wired for RJ12 or RJ13 is plugged into a jack wired for RJ14, the second line will be shorted when the phone goes off hook.

The networking folks love to call 8p8c connectors wired for ethernet "RJ-45", completely ignoring the fact that the USOC spec for RJ45 calls for a similar, but different connector (keyed, vs unkeyed), which is physically different from, and wired differently from ethernet. I can build a cable that fully complies with the requirements of RJ45, that will not plug into, nor have any electrical continuity with the contacts used for ethernet. It's kind of like trying to plug a 5-20P into a 6-15R, except there are more pins to choose from, and most of the time, things won't explode when you do so, although there are exceptions. (Don't plug a cable carrying a ISDN U interface into a cisco router aux port. chips tend to change from semiconductor to smoke state.)

Ethernet connectors do not have an RJ designation, despite the misuse of the RJ45 designation by the networking/computer industry.


My friend, if you have a PayPal account, I would be honored to buy you a drink. These misnomers have been causing me to beat my head against a wall for decades. "RJ45" is bad, and "RJ11" is even worse, but when I start seeing "RJ12", I want to go postal. These are wiring patterns that have NOTHING to do with the hardware itself. I already got myself kicked out of another EC forum over this issue, so I'm glad that I'm not the "bad boy" here. Thank you for popping the cork on this subject.

This rivals a "270" as being a NEMA 5-15 duplex receptacle, when in fact, it is Cooper/Eagle's part number for the device that can be configured to deliver this wiring configuration.



---Ed---

"But the guy at Home Depot said it would work."
Joined: Dec 2003
Posts: 886
H
Member
Back in the 60's and 70's I worked for a company that made automatic test equipment and one of my jobs was to come up with jigs for exactly what you are doing. I don't remember having to work with modular plugs but Google "Aines Manufacturing" and you will find some long 8 pos/8 pin test plugs. What I would do, after terminating a cable with them, is make a clamping arrangement out of aluminum and some machine screws to mount them where you need them on your jig. They should be long enough and you said you have access to a mill.

-Hal

Joined: Mar 2006
Posts: 15
C
ctardi Offline OP
Member
Hal...The K-Plug is Freaking Amazing! I will be giving Aines a call first thing tomorrow morning!

Techie...Thank you for the detailed explination! :-) I do appreciate my new found knowledge to be able to call these connectors by their proper names! (Now...if only other people would know what I`m talking about when I use the proper name...)


Proud Inventor of the Three Phase Light Bulb!

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