Icom Ct-17 Schematic

Once the MAX232 converts the PC’s Tx line to 5V logic, the signal flows into the opto-isolation stage.

This is the most critical section of the schematic. The original CT-17 design often utilized the (Driver) and MC1489 (Receiver) integrated circuits, which were the industry standard for RS-232 communication in that era. icom ct-17 schematic

A verified CT-17 clone schematic (common online): Once the MAX232 converts the PC’s Tx line

Some older Yaesu or Kenwood radios use standard TTL (non-inverted). You can invert the signal by adding a 74HC04 hex inverter between the opto output and the radio jack. The schematic’s open-collector design makes this easy. icom ct-17 schematic