Voice Keyer for FT-897 (and similar)
There are several voice keyers on
the marker already. However, I wanted something as small and
portable as the TCVR FT-897 is.
 The keyer is embedded into a small plastics box. It is plugged into the MIC cord. This way it doesn't require any extra power supply. |
 The keyer is controlled by the buttons on the MIC: UP - record DWN - play back FST - play repeatedly |
 All the parts are mounted on one single PCB including the two RJ-45 connectors. This is the top face of the board. |
 The bottom face of the PCB. |
Comments to the schematic:
For the recording and playback it uses Winbond ISD1730 chip.
CMOS 4053 switches the AF paths instead of a relay.
NE555 makes a delay around 3 sec between two playbacks.