Cat interface for Yeasu 980 HF radio. +9v to +12v (9v battery OK) +| | - Add DPST switch at X's TO IBM/COMPATIBLE ----------------O -X-||||-- | | | | | _|_ TO RADIO | < /// (Numbers shown are 232 CONNECTOR | <10 k for 6 pin din conn. | | < for FT-980 only) | | 1<----o--------------------------------------------o---------->(1) GND 7<----| | | | | | | | | |/|2 100 k | | 4/+|-----/\/\----|------------------------->(2) TTL | / | | | SIGS 3.3 k 1 / | | | | FROM 3<------/\/\-----/ U1A| | | RADIO \ | | | | | \ | | |\ | | \ |3 | | \| | | | \-|-----/\/\----o------| /|----o \| 100 k |/ | | | | 1N914 | -----\/\/------- (Radio Shack | | | | 100 k | 276-1122) | | |\ | | | 2<------/\/\--o--|-\ | | 18 k 6| \ | | /| | | | | \ 7 | |/ | | |U1B \------o----/\/\------|\ |----------o--->(3) TTL | / 47 | \| | | SIGS 2 | /11 1N914 | | TO | /| | | RADIO -----|+/ | U1 LM324 Quad Op Amp | | | 5|/ | (Radio Shack 276-1711) | ------ | | | /\1N914 | | Build circuit on bread- | / \ > | board(Radio Shk 276-175) | ---- > 100 k | | | > | - | | + | | | O --X---------||||---| | | _|_ -9v to -12v | | _|_ _|_ _|_ /// (9v battery OK) /// /// ///