A-190-4 is the replacement for module A-190-1 which is no longer avaiulable. The functions of A-190-1 and A-190-4 are nearly the same (Midi In, Midi Out, CV1, CV2, Gate, Clock, Reset). But the operation of the A-190-4 has been improved because a 3-digit LED display is available. The current values of all parameters (like Midi channel, reference note, clock divider) can be read back and modified by means of up/down buttons. In addition A-190-4 is equipped with an USB interface and the external +5V supply is no longer available. The module width is the same for A-190-1 and A-190-4.