Articles - DCC: Digitrax DS44 Stationary Decoder
The Digitrax DS44 was introduced in late 2001. It is the smaller brother of the DS54, and is only meant to be used for stall motor switch machines, such as the Circuitron Tortoise, which is what I happen to use. The DS44 is quite simple to install and operate. The two wires on the right of the decoder in the photo are the ones providing the power and control to the unit. I attach them to the DCC bus feed wires running under the layout. I attach the decoder with some velcro to the benchwork. The wires on the left are the ones that get connected to the Tortoise switch machines to control the position of the turnouts. See the instruction sheet as to which two wires are to be used for any one switch machine.
Digitrax DS44 Stationary Decoder
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This diagram shows how one of the four outputs of the decoder is connected to one Tortoise. I use a 1.68k Ohm resistor (actually a 1k Ohm and a 680 Ohm resistor in series) to perform a voltage drop. This voltage drop makes the Tortoise move slower, which is what I like. Beside that being more prototypical, it is also far less noisy in the room. For a crossover (where two turnouts are moved simultaneously) I put the Tortoises in parallel with each other and the resistor is changed to just a 680 Ohm value.
Digitrax DS44 Stationary Decoder