Soundcard Packet

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Joined: Sun Feb 10, 2002 8:00 pm

Soundcard Packet

Post by firemedic » Sun Sep 28, 2008 10:03 pm

Anyone build one of the soundcard packet interfaces? I'm using the optoisolators with a 4N25, I can get the RS-232 to swing everything right but the resistance across the emitter and collector of the 4N25 is too high (100 ohms) and won't key my PTT circuits. I don't really want to build a relay into the interface as I want to keep from using an external power source. Am I using the wrong optoisolator? I'm building this to a tee: ... #isolation

Using the isolation circuit. I dunno what I'm doing wrong as I did manage to get 1 circuit to work using a MCT2 optoisolator but I think I just got lucky with that one as the next one out the parts box does the same thing. Just wondering if anyone else had tried this and had the same problems as me. Thanks!!!

Keith L. Dobbins KC8RFW
W8TAP Repeater Technician
Parkersburg, WV 26104

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