S88-N adapter (PCB)

The S88 bus is probably the most widespread standard for connecting feedback decoders to a digital control unit. Most control units have a connection for the S88 bus.

The S88 bus is not very intelligent. In technical terms you can say that the S88 bus is not a data bus but a large shift register. The contacts are translated into bits and bytes in the feedback decoders. When the contacts are read, all those bits are pushed through a wire to the central unit. No error correction or other technology to prevent interference is applied.

Put an end to the disruptions

The S88 bus and the associated decoders are pleasantly simple and cheap, but interference signals from outside can sometimes result in a false occupancy message. There has been a lot of philosophizing about possible causes of malfunctions on the S88 bus. What certainly helps is to replace the standard S88 cables with network cables from the computer store.

Some hobbyists and manufacturers have made agreements about a standardized connection for RJ-45 connectors and network cables. This standard is called s88-N (sometimes also written as S88N). Decoders and peripherals with an s88-N connection can be recognized by the s88-N logo.

You obviously don't want to throw away your old decoders when you switch to s88-N. I designed a small PCB for an s88-N adapter. The PCB consists of two halves: an adapter from a standard S88 bus strip connector to S88-N and an adapter that does exactly the opposite.

The idea is that you just saw through the PCB, so that you have two complementary adapters. You plug the adapters into your decoder so that the white arrows point towards the central unit. Your old decoder has now become an s88-N compatible decoder.

More information

Visit the Adventure in Miniature website for more information, components and connection diagrams.