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| DB9 Connector Pin 3 (TXD) |
| FSK to Radio |
| Ground is on the DB 9 Connector Pin 5 |
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| FSK Circuit |
| PTT Circuit |
| CW Circuit |
| Simple
Interfaces for FSK, PTT & CW Keying Updated 08/01/2007 |
| DB9 Connector Pin 7 (RTS) |
| CW to Radio |
| Ground is on the DB 9 Connector Pin 5 |
| DB9 Connector Pin 4 (DTR) |
| Ground is on the DB 9 Connector Pin 5 |
| PTT to Radio |
| These are the exact circuits I use for FSK, PTT and CW keying with WriteLog, but they should work for any other program as well. The PTT & FSK circuits work great with MMTTY. These circuits are connected to the same DB 9 connector to the same serial COM port on the PC. The transistor can be just about any general purpose NPN transistor. I use the ECG 123 (same as NTE 123). The 2N3904 works fine too. The resistor value can be just about anything from 500 to 2k ohm or possibly lower or higher. 1k ohm worked great for me. Pin 5 on the DB 9 connector is common to all circuits. However, you may not need all three interfaces. You can build them as single units or two in one, it doesn't matter. For instance, for WriteLog, I don't need PTT because it is done by computer control of the radio. |
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| Ron, ND5S, built his interface into a very nice looking box (left photo) with a short pigtail coming out to the DB 9 connector (which is female). The box is Radio Shack p/n 270-1802. He used 3 chassis mounted RCA jacks. Says Ron "The label was made on PowerPoint on plain paper affixed with two way carpet tape and covered with clear contact paper." Ron's PowerPoint file is available for download. The template is pictured below. Download here. |
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| Thanks Ron! |
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| Build an FSK interface inside your RigBlaster Nomic - details from Gert, K5WW, here! |
