SPROG II gives you the ability to program DCC decoders using your computer without the need to move your computer to the railway room, or your existing DCC system to the computer room. SPROG II accepts commands from the computer's USB port and formats them into DCC packets for programming of decoders or operating small layouts or DCC accessory systems. More than just a programmer SPROG II is capable of generating any valid (or invalid) DCC packet to facilitate testing of DCC components. This was originally intended for use with a small 'tailchaser' test track or rolling road for decoder testing, running-in, performance tuning, etc. DecoderPro includes a throttle for SPROG II allowing it to be used as a computer based command station/booster for small layouts with "one loco in steam". An external booster may be used with SPROG to allow larger layouts to be driven. Other possibilities include using SPROG II as an interface between PanelPro and a DCC accessory bus.