In the figure we have a circuit that allows to interface TTL logic with TTL logic, but with total isolation of the signals. The data transmission speed can be adapted by adjusting the Rin and RL value. The following table provides values for some data speeds depending on RL and Rin.
Table:
Datasheet of L (ohms) | Rin(ohms) | IF (mA) | f(max) (kHz)
Datasheet of 200 | 1800 | 1,7 | 40
Datasheet of 70 | 390 | 8 | 125
Datasheet of 00 | 180 | 17 | 150
