controlled by the 6040 Keyboard. Up to ten controllers could be added to the right hand side of the Central Unit, and up to 16 keyboards could be added to the left hand side, with each keyboard controlling 16 accessories (signals, turnouts, lights, etc.) for a total of 256. For large layouts 6016 Boosters and their own power supplies would provide additional power to layout sections with all Boosters linked to the Central Unit by a ribbon cable. A later accessory was the 6043 Memory, which was used for switching predefined routes each with multiple turnouts & signals. The 6043 could save up to 24 different routes, which each route containing up to 20 individual device commands. The 20th command in one route memory could be used to link to another route button, so there could be a large number of individual commands enacted by pressing one button. In addition, the 6088 s88 Feedback Module could be used in conjunction with the 6043. The s88 would receive input signals from external buttons or magnetic reed switches and then start a command string in the 6043 Memory. So, an approaching train could set up its own route, as an example. Another accessory was the 6050 computer Interface which let the system be computer controlled, allowing for fully automated train control. Decoders The first c80 (6080) decoders did not have motor regulation (speed control) and the 1991 introduction of c90 (6090) decoders with regulation and a 5-pole DC motor brought the system to maturity. Decoders had miniature switches (DIP switches) to set the address and c90 decoders had two potentiometers to adjust braking / acceleration delay ("inertia") and maximum speed, requiring the use of tools to open the model and make any changes to settings. Accessory decoders Signals, turnouts, uncouplers, lights, and other static accessories may also be fitted with decoders which have their own address range for up to 256 switched devices. Depending on the decoder, either continuous power (lighting) or momentary (signal, uncoupler, turnout) is provided. K83 decoders are for solenoid (momentary) accessories and K84 for lighting (continuous) accessories, each one controlling up to 4 devices. Automatic braking Automatic braking allows a locomotive to coast relatively gently up to a stop signal at danger. When fed with negative DC the decoder will slow the locomotive smoothly. Track must be sectioned at least once, the stopping area before the signal, and