The Digitrax TF4 is a quad-function DCC decoder with integrated transponding — four independently controlled function outputs on one tiny board, plus Digitrax's position-tracking feature built right in. Perfect for adding ditch lights, mars lights, rear markers, classification lamps, smoke generators, or any other DCC-controlled accessory cluster to a non-decoder locomotive. Looking for more DCC decoders and electronics? Browse our DCC Decoders and Electronics & Wiring collections. Features Four independent DCC-controllable function outputs (white, yellow, green, purple) — control each one separately via your throttle. Integrated transponding — Digitrax position-tracking built in, no separate transponder board needed. 1A continuous, 2A peak combined function output — plenty for headlights, ditch lights, rear lights, smoke, or accessory clusters. Hardwire install with color-coded leads — works in HO, N, O, S, and G scale. Full CV programming including FX3 lighting effects (Mars, Gyralite, Strobe, Random Flicker, Soft On/Off, Rule 17, etc.) on every output. SuperSonic silent-running operation, NMRA DCC compatible. More Information Brand Digitrax Item Number TF4 Type Quad function-output DCC decoder with transponding Function Outputs 4 (white, yellow, green, purple) — 1A continuous combined Motor Output None — function-only decoder Transponding Integrated (no add-on board needed) Connection Hardwire — color-coded leads Scale Compatibility HO, N, O, S, G (any DCC scale) Condition New — sealed UPC 652667100083 FAQ What's the difference between the TF4 and the TL1?The TL1 has one function output; the TF4 has four. If you need to control multiple separate lighting circuits (headlight + ditch lights + class lamps + rear marker) the TF4 is the right call. Both have integrated transponding. Does this drive a motor?No — the TF4 is function-only. For motor + lights in one board, use a full mobile decoder like the Digitrax DH126 or DZ126. What can I wire to the function outputs?LEDs (with resistors), incandescent bulbs, smoke units, ditch lights, mars lights, signal lamps, sound modules — anything DC-driven under 1A combined draw. FX3 effects make each output simulate prototypical lighting patterns independently. Will it work with any DCC system?Yes — standard NMRA DCC. Transponding readback requires a Digitrax LocoNet command station with detection sections (BDL168, BDL16, etc.).