software update. This had many of the enhancements offered by CS2, including track layout views for controlling signals and turnouts, and large cab view locomotive control display. Model numbering From the 1950s Märklin models had four digit numbers, the first two being the group and the last two the individual model. Locomotives fitted with the original c80 digital decoders were numbered 36xx (36 followed by two digits e.g. 3615) and the first models fitted with c90 decoders 37xx (e.g. 3702). In 1997 Märklin had to expand the numbering to five digits 37xxx and a few new c90 equipped models were numbered with five digits before the c91 decoder was fitted to all subsequent models. New 36xxx models are budget models fitted with low cost digital decoders lacking motor regulation. When Märklin introduced the specially developed C-Sine motor in 2000 these models were numbered 39xxx, some were also produced as 37xxx. H0 digital upgrade Märklin offered many different decoders and kits to upgrade analog locomotives to digital control. A digital decoder was the basis and many kits also included a permanent magnet and 5 pole armature to upgrade the motor and convert it to DC (such decoders rectify track current to DC for the motor and any accessories, such as lighting or sound). For many years, unlike Digital Command Control, Märklin did not use a plug in connector for the decoder and so conversion involved soldering output wires. Most decoders also provide motor regulation (speed control) with adjustments for acceleration & braking delay (artificial inertia) and maximum speed. DELTA decoders never provided motor regulation and originally had to be set to address 0 for analog operation. mfx decoders provide many additional motor control parameters, all adjusted using the main controller (Central Station) or a computer. Märklin locomotives had several motor types and many upgrades were for a particular version. First generation conversion kits Almost all the first generation decoders had DIP switches to set the address and potentiometers to set motor regulation, requiring tools to open the model and make adjustments. The motor parameters are maximum speed and artificial inertia, in other words the delay after making a speed change on the controller and the response of the decoder, which allows smooth transitions. 6080 Decoder for all AC locomotives. No motor regulation, 14 speed steps, 1 switched function. 6081 Decoder for all DC locomotives. No motor regulation, 14 speed steps, 1