I understand there are 8 or 9 pin decoder's, harness and/or plugs. Can you use an eight pin decoder with a 9 pin plug or vice versa? What is the ninth pin for? I'm just starting my journey in decoder installation after 4 years of just running decoder equipped loco's some with sound. Also I would like to find out what is the dirfference between a 2 function decoder and a 4 function decoder in simple terms?
Thanks in advance, Jim
Two different things. The 8 pin plugs are 2 rows of 4 pins. On the loco there is usually a socket to plug this in, on the deocder side, this 8 pin plug is usually at the end of some length of wire.
The 9 pin plug is a linear design - 9 pins all in a row - and is normally at the decoder end. The other side of the 9 pin plug may be wires that get sodlered to the loco, or even one of the 8 pin plugs, plus a spare wire.
The 8 pin plug allows for track power (2 pins), motor power (2 pins), function common (blue wire), F0 forward, and F0 reverse. The extra pin is usually left disconnected and the pins are arranged in such a way that if you plug it in backwards, nothign will be damaged. The 9 pin plugs usually contain the same things, plus F1 and F2. All 9 are used, but the design of the connector is such that it an only be plugged in one way.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker Two different things. The 8 pin plugs are 2 rows of 4 pins. On the loco there is usually a socket to plug this in, on the deocder side, this 8 pin plug is usually at the end of some length of wire. The 9 pin plug is a linear design - 9 pins all in a row - and is normally at the decoder end. The other side of the 9 pin plug may be wires that get sodlered to the loco, or even one of the 8 pin plugs, plus a spare wire. The 8 pin plug allows for track power (2 pins), motor power (2 pins), function common (blue wire), F0 forward, and F0 reverse. The extra pin is usually left disconnected and the pins are arranged in such a way that if you plug it in backwards, nothign will be damaged. The 9 pin plugs usually contain the same things, plus F1 and F2. All 9 are used, but the design of the connector is such that it an only be plugged in one way. --Randy
Hey thanks Randy, that makes sense now ! LOL I've seen the pictures, should have guessed that was it. Most of my loco's came equipped and I've only taken apart one, and sent it back after plugging in a decoder and still didn't work. I just recently bought 2 BLI sound equipped but DC. I ordered actually 4 digitrax decoders that were recommended for them, they were 4 function decoders and I don't understand the difference between 4 function and 2 function. I have pre ordered 2 others BLI loco's with DC and sound. Jim
Jim,
"All" decoders (except accessory decoders) provide for track power in and motor power out. In addition, a decoder may have anywhere from two to six additional functions. Typically the first two (the only two for a two function decoder) are for the forward and reverse lights. Additional functions are typically for additional lighting effects, such as ditch lights, roof top beacon, etc.
skagitrailbird Jim, "All" decoders (except accessory decoders) provide for track power in and motor power out. In addition, a decoder may have anywhere from two to six additional functions. Typically the first two (the only two for a two function decoder) are for the forward and reverse lights. Additional functions are typically for additional lighting effects, such as ditch lights, roof top beacon, etc.
Thanks Roger, that explains why one of my Atlas engines and another have 4 funtion decoders, the ditch lights and mars lights. Funny I thought I was quite content just running my loco's out of the box. Since I got the PR3 and JMRI I'm rather enjoying learning more and trying new things. I appreciate the information. Jim
Remember if you want ditch lights that alternate back and forth, you need 2 functions just for them. If your road doesn;t do the alternating flash, you can connect both lights to a single function. From the factory I believe many models with operating ditch lights connect them both together, so when plugging in a decoder they will come on together with a single function. You have to do a bit of rewiring to make them flash alternately. For forward and reverse lights, plus ditch lights and a mars light, that's 5 functions. Typically, 6 is the most you'll find on an HO decoder. There are function-only decoders that you can add if you have that many lights or effects, these get programmed to the same address as the motor decoder but have their function outputs programmed to work on additional F keys.