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What are good solutions for pluggable, "free-hanging" cable connections?

As simple as this question might sound, I am currently struggling in finding components that allow me to easily connect and disconnect a set of cables. This is my scenario:

I have three devices using the Modbus/RTU protocol over RS-485 three-wire cables. I have to connect and disconnect these cables from time to time: For instance:

  • I have devices A, B, and C.
  • A and B can be connected together, and A and C can be connected together.
  • From time to time, I have to unplug A and B and connect together A and C.

Therefore I am looking for a cable connection that allows for the following:

  • Initial assembly of the cable's connector/receptacle should be easy and reversible: No fancy crimping tools, no soldering. Just screwing the cable to the plug. Or a spring-cage connection.
  • Connector and receptacle shall protect against polarity mismatches (i.e., there is only one way of plugging connector and receptacle together).
  • Plugging and unplugging the cables shall be easy.

By now, I have spent half a day of finding viable solutions. The only solution I have found so far is a combination of MSTB 2,5/ 4-ST-5,08 and IC 2,5/ 4-ST-5,08.

How do you connect cables together?

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  • \$\begingroup\$ To be clear, are you wanting a cable which connects to jacks on your device correct? Or are you intending to have this connected directly to the PCB? \$\endgroup\$ – Daniel B. Sep 7 '14 at 19:11
  • \$\begingroup\$ @DanielBall, PCB shall not be involved in this setup. I'm looking for endings on cables that fit together. Something like the connector and receptacle involved in pairing a USB cable with a USB extension cable, but without soldering and without any other "destructive" assembly steps. \$\endgroup\$ – Abdull Sep 7 '14 at 20:52
  • \$\begingroup\$ Can't you use a SPDT switch to make the connection from a to b on one side and from a to c on the other \$\endgroup\$ – deathismyfriend Sep 8 '14 at 19:04
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FCI, and Molex both make a line of plugable screw terminals if you want to go that route.

http://portal.fciconnect.com/portal/page/portal/fciconnect/producttype?appname=catDisplayByPath$entryPoint=adir%20%20ect$categoryPath=Product%20Type

http://www.molex.com/molex/products/family?key=eurostyle_terminal_blocks&channel=products&chanName=family&pageTitle=Introduction&parentKey=terminal_blocks_and_barrier_strips

http://www.molex.com/molex/products/family?key=mtc_multi_terminal_connector&channel=products&chanName=family&pageTitle=Introduction&parentKey=terminal_blocks_and_barrier_strips

A better idea might be to use ribbon cable with shrouded headers. The shroud will give you the polarity protection you want. You don't need any special crimping tools to make the ribbon cables they just snap together. Here are some links to examples of 6-pin cables in a 2x3 header. These are really common and come in many sizes though.

https://www.sparkfun.com/products/10651

https://www.sparkfun.com/products/10650

https://www.sparkfun.com/products/10646

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  • \$\begingroup\$ molex pluggable screw terminal part number please? \$\endgroup\$ – ACD Sep 8 '14 at 17:38
  • \$\begingroup\$ Updated answer with links to Molex's product selection site with relevant products. \$\endgroup\$ – Pete Sep 9 '14 at 18:02
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What about solder-type Dsub connectors? No special crimping tools, just a soldering iron or a screwdriver. A single m/f pair would run you about a dollar (not including backshells, 2-3 each for those probably). It meets your requirements, though they could be pulled off by accident, did you need some sort of locking mechanism?

D-sub 3 (expensive) D-sub 9 (cheaper. Link provides filter for crimp, push fit, screw terminal types)

Maybe XLR connectors? Only wire strippers required. Male Female.

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