The KL2502 output terminal modulates the pulse width of a binary 24 V DC signal and outputs it electrically isolated from the K-bus. The mark/space ratio is prescribed by a 16 bit value from the automation device.
The KL2521 output terminal alters the frequency of a binary signal and (electrically isolated from the K-bus) outputs it. The frequency is preset by a 16 bit value from the automation unit.