αSTEP/Stepper Motor: Relationship Between Cable Length and Transmission Frequency

The longer the pulse line, the lower the maximum transmission frequency.
This is because the resistance and stray capacitance of the cable causes a CR circuit to be formed, which delays the rise and fall of the pulse.
The stray capacitance of the cable occurs between the wires and between the wires and the ground. It is difficult to give a definite value because conditions vary depending on the type of cable, wiring, routing, etc.