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Digitrax's SE8C signal controller can drive up to 32 signal heads. It is what's called a "dumb controller". It has no logic on board to determine which LED should be on or off. All it does is turn LEDs on and off according to the commands sent to it by some other logical device - a computer, for example.

Team Digital's SIC24 has 24 outputs, each of which can control one LED or other device such as a Tortoise to control a turnout, semaphore, train order board, or crossing gates. If all your signaling is three-aspect, for example, the SIC24 can control up to 8 signal heads. With two-aspect signaling, it can do 12 signal heads. But what makes this really different than Digitrax's signal controller is that it has full logic built in for each output. This means that each output can make its own determination as to whether the LED should be on or off - based upon block detection, turnout position, or other criteria. The SIC24 can even determine how an SE8C-controlled signal should be and send it a command to do that. In fact, Team Digital is working on another board that would provide logic for Digitrax's SE8Cs without having to use a computer. It would also provide additional logic for the SIC24 when complex situations need more logic than is built in for each output.

The cabling system described below is designed to be plug-n-play directly with Digitrax's SE8C. Because Team Digital's SIC24 doesn't have the same pin out as the SE8C, it won't work directly with the complete cabling system as-is. But, there are three solutions: 1) You can simply wire the signal to the signal base differently than intended, 2) don't use a signal base and wire the signal to a header that will plug into the signal cable, or 3) use an adapter that Team Digital is working on. All this is explained below.

You can slip the cable through the gap between the 'teeth' and top, then crimp, or take it apart (shown at right) to put back together with the cable between the two pieces.

Here's what it will look like when put on the cable ready to crimp, and then crimped.

But how do you do the crimping? Well, there are tools to do it with - if you can find and afford them. We use a special tool to do the crimping when you order pre-made cables (yes, we make custom cables for the price of the parts plus 90¢ per connector crimped on). But we do a lot more crimping than you will, so you may not want to spring for a special tool. Crimping can also be done with Channel Lock-type pliers, a vice, a drill press, even a small hammer.

If using pliers, open them up to the general size of the connector. If the opening is too large, use a piece of plastic or wood to fill up the gap - to insure good flat contact between the pliers' jaws and parts. When squeezing the parts together, be especially careful that the parts are going together straight and evenly, and don't squeeze any harder than necessary to get the two parts to come together.

If using a vice, put the parts in square and be sure they stay square when squeezing them down. Be sure to not squeeze the parts together any tighter than necessary to get the two parts together.

A drill press can be used like an arbor press to do this. All you have to do is find something that will provide a flat surface when chucked up into the chuck. You may be able to find a drawer pull, for example, with a flat surface. Even if you can't find one with a flat surface, you can grind or sand a flat surface on it. An old wood drawer pull would be easier to do this with than a metal one. Screw a screw in as far as it will go, then cut the head of the screw off. Now you can chuck the screw up into the drill press and use the flat surface of the pull to press the two parts together between it and the press table. Again, be sure to not press any harder or further than necessary to get the two parts together. NOTE: Do not turn the drill motor on. You're just using the press part of it.

If using a small hammer, use several light blows rather than one hard blow. Be sure to not strike the parts any more than necessary to get them to go together. In fact, it would be wise to place a small piece of wood on the part to cushion the blows.

In any case, be careful to make sure the parts are going together straight, and that you're not using more pressure than necessary . These are plastic parts and can break. Be prepared to mess up one or two until you get the hang of it. Start with a cable that is a few inches too long, and crimp the two end connectors on first. This way if you mess one up while getting the hang of doing it, you can simply cut it off and try it again.

Notice that connectors are crimped onto the cable in various positions. This is to accommodate plugging one end onto the signal control board, and the others at intervals necessary to reach the signals they service. You may need to twist and turn the connector into the correct position to make the signal face in the proper direction, so it's wise to provide extra length from one connector to the next for that purpose.

Some notes:
Each cable can control up to four signal heads. There are two heads on each Signal Base. If you plug the base into the connector one way, it controls heads 1 and 2. Plugged in the other way controls heads 3 and 4. If you crimp a connector on backwards, it's OK - just ignore the pin #1 mark on the connector and plug the signal base in in relation to the cable's conductor #1.

Keeping this (plugging in in relation to conductor #1) in mind, here's something else to remember. Let's say that if you crimp your connector onto the cable as it lays flat, your signal would be facing in the wrong direction. This would mean that you'll have to take the cable beyond that spot to make it make a "U" turn so it will face in the opposite direction. Instead of doing this, simply crimp the connector on the cable upside down, then twist the cable to make the connector face upward for the signal to plug in.

Notice in the photos at right that conductor #1 stays on the same side when the cable lays flat, but goes to the other side when twisted. By twisting conductor #1 to the other side, you have effectively reversed the direction the signal will face when plugged in.

Digitrax's D-SDCK kit provides 20 feet of cable and 8 connectors. We also offer the cable and connectors individually: the colored cable (M-RIBN10c) is 26¢ per foot, the gray cable (M-RIBN10) is 15¢ per foot, and the connectors (M-IDC10) are 35¢ each. This allows you to order exactly what you need and save some money in the process.

This is the neatest part of Digitrax's signal wiring scheme, and deserves the 'most innovative' new product award for 2003. This is a triple-purpose item that makes signal mounting and maintenance a walk in the park.

1) You first use it to test the signal controller board. Then you use it to assist you in the proper installation of your signal cable. You then use it to test your cable. With everything installed and tested with this device, there's no wondering about whether your cable or signal connection is the problem if it doesn't work correctly.

2) Next, you can use it as a temporary signal - until you can afford to buy the scale signals of your choice. It's designed for N scale, but can be reasonably used for HO scale temporarily. If you don't need two heads, snip the top one off or just ignore the one not being used. Without something like this, you may not be able to signal your entire layout all at once due to limitations of funds for all those scale signals. But most people can afford $4 each for these, and start getting the benefits of signaling right away.

Additionally, this allows you time using your new signaling system to be sure that it's correct. After a little use, you may find that you didn't think of something and need to change your original plan. Doing this with these signals is a piece of cake, and not very expensive. Doing that with scale signals could be costly if you wind up with a signal different than what you need.

3) Here's the kicker. As you replace these signals, one by one as you can afford scale signals, you don't throw these away. You snip the mast off and use the base to mount and wire the scale signal to. You can then simply plug your new signal onto the layout. Being able to wire your signal to a plug-n-play device allows you to do this work at the bench - not just for initial installation, but for any needed service work later; no soldering work under the layout.

The illustration at right shows a signal mast mounted to a base.

There is a long solder pad, with four holes flanking it, for mounting the mast to the back of the mast base. There are two ways to mount the mast, depending on your skills and the type of signal wires used: 1) Soldering the mast to the board without tying, 2) tying and then soldering. The photo above shows the mast tied and soldered. Regardless of which method you use, the first step is to clean the bottom part of the mast before you start - so solder will easily bond to it.

Soldering the mast directly to the board is the quickest and easiest way. However, there are a couple of reasons why you may not want to do that: 1) if the wires inside the mast are not heat-resistant, you don't want to use any more heat than absolutely necessary, or 2) if you're a bit shaky and/or can't rig some sort of device to hold everything in place while soldering.

Teflon®-coated wires are heat-resistant, as is varnished wire. Tomar uses Teflon-coated wire. Oregon Rail Supply uses varnished wire for their pre-assembled signals. If you're not sure of the wire in your signals, you can test it - use your soldering iron to apply a little heat to the insulation on the end of one wire to see what happens. If it instantly melts away, you don't want to solder the mast directly.

Soldering directly to the base:
If soldering directly to the base, there is solder on the mast pad already. All you have to do is place your mast in position and apply heat. But be sure you have the signal facing in the exact correct position when soldering - the same way the temporary mast was facing. If you solder it on facing some other direction, you'll have to remount the cable connector accordingly.

For people with a good eye and steady hands, this is a piece of cake - quick and simple. But if you're a bit shaky, you'll need to use a third hand, or other securing device, to hold the mast in place while soldering. Keep in mind that when the solder on the board melts, the mast will get closer to the board. This means your holding device should be such that the mast will stay straight and true when this happens.

If you're not comfortable with that, you can remove the solder with solder wick or other solder-removing method. If using solder wick, be sure that you're skilled with it. Too much heat can damage PC board traces. But once the solder is removed, you can mount the mast tight in your holding rig and solder with rosin-core solder.

Tying and Soldering:
First, remove the solder from the mast pad and the four flanking holes. Use two short pieces of solid-core phone wire with the insulation removed. Tie the mast in position with the wires by stringing them around the mast and though two opposite holes. Twist the wires to secure the mast tight to the base. Once this is done, be sure the signal is positioned squarely with the board, and facing in the correct direction.

If you're doing it this way just to have the mast held in place with wires while soldering, simply solder the mast to the board. It doesn't matter whether the holding wires are also soldered to it or not. If not, you can remove the wires afterwards. Otherwise, there's nothing wrong with leaving the wires there. But, you could snip the twisted tails off so they won't hang up on anything when mounting the signal on the layout.

If you're doing it this way because the signal wires are not heat-resistant, you have to carefully solder each of the phone wires to the mast with a tiny drop of solder. The best tactic is to use a really hot soldering iron, put a drop of solder on the tip of it, then place that drop on the tie wire only long enough for it to flow around the wire and to the brass mast tube. Do one and let it cool before you do the second one. Once that is done, and fully cooled, you can solder the wires to the PC board at the holes they go through. You can snip the twisted tails off when finished.

Our suggestion, if you're wiring your own signals, is to use Teflon wire like Tomar uses - so you won't have to worry about it.

After mounting the mast to the signal base, connect the signal wires to the appropriate pads, according to the instructions that come with the Signal Mast Base Kit. Note: since you may be using these as signals for a while before cutting them off and mounting your signals to them, be sure to not lose the instructions that come with them.

When done, simply plug the signal back into the cable connector from where it came.

Note that the standoffs may be too long. Unless you have exceptionally thin sub-roadbed, you're likely to have to cut the standoffs off to achieve the correct height. Also, because the signal needs to be plugged into the connector in the correct orientation, the cable may need to be taken beyond the signal location and doubled back, maybe even twisted, to get the connector into the correct orientation (shown in the Securing Ribbon Cables section below). But, once that's done using the D-SMBK, it will still be correct when you snap the mast off of it to replace with your scale signal - just be sure to mount the mast onto the base in the correct orientation.

Velcro™ can also be used for securing ribbon cable (not the connectors) - there are two ways to do it. If you are securing just one 10-conductor ribbon cable, all you need to do is stick, screw, or tack one part of the Velcro to the bottom of your bench work, then sandwich the cable between it and the other piece, as shown here.

The photo shows our VEL holding the ribbon cable. While this is more expensive than our vinyl brackets, it's much less expensive than Digitrax's metal brackets, and just as handy. To reduce the costs, you could buy our Velcro™ by the foot (VELf) and cut the pieces a little shorter.

As you can see, the two parts are overlapped by about 3/8" and screwed to the bottom of the bench work. The wires can be held in place while attaching the free ends of the A/B parts of the Velcro. The nice thing about this method is that it is readily adjustable to fit the wires, and there is no unscrewing and re-screwing to take the wires out and put back. Again, this is done with our 1.75" strip of VEL.

At only 25¢ for each header (M-Header), 10¢ (or less) for each resistor, and a little bit of shrink tube, this is the lowest-cost method of connecting your signals. The illustration at right shows the pin out of the cable socket as used with Digitrax's SE8C. Note that the "1" inside the triangle indicates pin #1.

Up to four three-aspect signal heads can be wired to this connector. Keep in mind that to do this, there will be two wires, from two different signal heads, attached to each pin.

G/H (Green), Y/H (Yellow), R/H (Red), and A/H (Auxiliary) are the connections for two signal heads - one signal head using the C/E common, the other using the C/W common.

G/L (Green), Y/L (Yellow), R/L (Red), and A/L (Auxiliary) are the connections for two more signal heads - one using the C/E common, the other using the C/W common.

Using different commons is how you can get different signaling from two heads using the same LED color connections.

You can also use this same cabling with headers directly with Team Digital's SIC24, without their adapter board. Just use the standard pin out connection shown in their documentation.

Lastly: It's good practice to use a separate resistor for each LED. Sometimes using a separate resistor for each LED is required. For example, different colored LEDs sometime require different resistor values. And if there's a possibility two LEDs would be on at the same time, a resistor that's right for one LED being on would be wrong for having two on. However, if the LEDs on your signal all require the exact same resistor value, and you're absolutely sure that two LEDs will never be on at the same time, and your signal controller doesn't require you to use three separate resistors for one reason or another, you can use a single LED on the common for all the LEDs rather than one resistor for each LED.

Using the same connections (with different commons) for two heads like this is called multiplexing. The illustration at right should help you understand how this works.

Even though both signals are connected to the same green/yellow/red connections, signal head #1 is connected to common #1, and signal head #2 is connected to common #2. For this discussion, let's say that signal #1 has the green LED on, and signal #2 has the red LED on.

For a split second the processor on the SE8C will connect power to "1" and "G" to light up LED "1/G". LED "2/G" doesn't light because it's connected to common #2 which isn't powered. Then, for the next split second, those connections are disconnected so it can apply power to "2" and "R" to light up LED "2/R". LED "1/R" doesn't light because common #2 is not powered at this time.

It flips back and forth between powering these two LEDs like this until one of the signals changes. Even though each of the LEDs is only powered half of the time, it switches back and forth so fast that the eye can't see them go off.