TS-940 Ultimate Computer Interface
To enable me to use serial-port driven RTTY, I created an interface which connects RTS to PTT, DTR to the CW key, and TX to the FSK input. It also will optionally mute the mic input when PTT is high, of have DTR control the mute instead of the CW key (configured via jumpers). I had the board made by OSH Park. Of course, my initial connected the Q2 transistor incorrectly, so the one transistor is mounted weird.
The input is a standard DE9 port, and the outputs are two RCA connectors (for CW and FSK), and a DIN connector which connects to the ACC 2 port on the rig.
Notice that the audio from the rig to the computer is DC blocked. Computer sound cards like to apply bias, and we don’t want that getting into the rig.
You can download the Gerber files order the board via the shared project on OSH part if you want your own board. I would share the KiCad files, but there’s a number of custom footprints, and I have a copy of the whole library in the directory, so cleaning it up to put here would be a pain.
Here is the order I placed from Digi-Key:
| Qty | Part Number | Mfg. P/N | Description | Unit Price | Extended Price |
|---|---|---|---|---|---|
| 2 | 2N3904FS-ND | 2N3904BU | TRANS NPN 40V 0.2A TO-92 | 0.220 | $0.44 |
| 1 | 2N3906FS-ND | 2N3906BU | TRANS PNP 40V 0.2A TO-92 | 0.270 | $0.27 |
| 3 | CF14JT1K00CT-ND | CF14JT1K00 | RES 1K OHM 1/4W 5% AXIAL | 0.100 | $0.30 |
| 20 | 5-146858-1-SI-ND | 5-146858-1 | CONN HDR BRKWY .100 VERT GOLD | 0.143 | $2.86 |
| 2 | 1N4148FSCT-ND | 1N4148TR | DIODE GEN PURP 100V 200MA DO35 | 0.100 | $0.20 |
| 1 | 493-15032-ND | UES1H010MDM | CAP ALUM 1UF 20% 50V RADIAL | 0.460 | $0.46 |
| 10 | S9001-ND | SPC02SYAN | CONN JUMPER SHORTING GOLD FLASH | 0.059 | $0.59 |
| 2 | CP1-3523N-ND | SJ1-3523N | CONN JACK STEREO 3.5MM R/A | 0.830 | $1.66 |
| 1 | A32092-ND | 5747840-4 | CONN D-SUB PLUG 9POS R/A SOLDER | 2.020 | $2.02 |
| 1 | CP-1402-ND | RCJ-013 | CONN RCA JACK MONO 3.2MM R/A | 0.830 | $0.83 |
| 1 | CP-1404-ND | RCJ-015 | CONN RCA JACK MONO 3.2MM R/A | 0.830 | $0.83 |
| 1 | HM891-ND | 1455J1202 | BOX ALUM NATURAL 4.72”LX3.07”W | 14.530 | $14.53 |
| Subtotal $24.99 |
You can download this order as an .xlsx file.