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8 and 9 pin differences

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  • Member since
    February, 2002
  • From: Mpls/St.Paul
  • 11,131 posts
Posted by wjstix on Friday, May 17, 2019 2:38 PM

Of course, since for years most "DCC ready" engines have had an eight-pin receptacle, I suspect a large number of non-hardwired 9-pin decoders were installed by using a 9-pin to 8-pin harness. Some engines have come from the factory with connections for either 9 or 8 pin decoder installation, but I suspect a majority just have the 8.

Stix
  • Member since
    February, 2002
  • From: Reading, PA
  • 26,091 posts
Posted by rrinker on Thursday, May 16, 2019 9:45 PM

One?

But the real answer is 2. Yes, ever schoolkid knows 8 from 9 is 1, but in decoders it's 2. The 8 pin connector is designed to have one pin not used, so really it only has 7 connections - this allows the ham-fisted to plug the thing in backwards and not actually hurt anything - the loco will just run backwards. The 9 pin conenctor is physically keyed, so it can;t be plugged in backwards, so all 9 pins are used. This gives you the track, motor, headlights, plus 2 extra finctions, and the function common.

 Plenty for me, my era has no ditch lights, no beacons, no gyralights. Headlight on the front and back of the loco, that's it. 

 But as mentioned the 21 pin conenctor is replacing all of thenm, this allows many more functions to handle all those modern fully detailed locos with headlights, beacons, ditch lights, workign number boards, cab lights, and step lights. Plus the speaker wires for sound. Who knows, maybe some day even 21 pins won't be enough and they'll come up with somethign else.

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May, 2010
  • 5,417 posts
Posted by mbinsewi on Thursday, May 16, 2019 8:30 PM

ndbprr
Obviously 9 pin connections have superceded 8 pin connectors. 

Just to clarify, I use a 6 function decoder, it has the 9 pin plug from harness to decoder, but the harness still plugs into an 8 pin connector on the locomotive's board.

The 6 function decoder allows me to configure ditch lights, the way I want, using the green and pruple wires, but it all still plugs into the 8 pin connector on the loco.

Even the 2 function decoder I use still has 9 pins (wires) between decoder and harness.  As long as I have been using decoders, about 8 years? all decoders have 9 wires in the harness.

Mike.

 

  • Member since
    December, 2015
  • 5,314 posts
Posted by BigDaddy on Thursday, May 16, 2019 6:12 PM

ndbprr
What are the advantages and reason for the switch?

I don't have any 9 pin, tell us about the switch.

Henry

COB Potomac & Northern

By the Chesapeake Bay

  • Member since
    June, 2004
  • From: From Golden, CO living in Puyallup (Seattle), WA
  • 616 posts
Posted by Renegade1c on Thursday, May 16, 2019 5:36 PM

8 pin connectors really only do the headlight and taillight. 9 pin connectors will do two extra functions on top of that. Even the 9 pin connectors are starting to get phased out with the 21 pin PEM connectors. 

The 21PNEM connectors are coming on a lot more decoders these days. 

Doesn't surprise me though since now you have sound, working everything lights (class lights, number boards, etc.)


Colorado Front Range Railroad: 
http://www.coloradofrontrangerr.com/

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  • Member since
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  • 6,801 posts
8 and 9 pin differences
Posted by ndbprr on Thursday, May 16, 2019 5:26 PM

Obviously 9 pin connections have superceded 8 pin connectors.  What are the advantages and reason for the switch?  Thank you.

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