The digital input terminals KL1488 and KL1498 (negative switching) acquire the binary control signals from the process level and transmit them, in an electrically isolated form, to the higher-level automation unit. The Bus Terminals contain eight channels which indicate their signal state by means of light emitting diodes. They are particularly suitable for space-saving use in control cabinets. By using the single-ended connection technique, a multi-channel sensor can be connected in the smallest space with a minimum amount of wiring. The power contacts are looped through.