This unique design, originally developed for SSTV use, has many other applications (RTTY,PSK, Packet etc). The Auto Muting interface is self powered and works with transceivers using a normal dynamic microphone. (A similar device is available for 'ICOM' electret types). It can also route received audio from the
mic. socket (an extra cable could be added for this). With a suitable (HamComm, VOX Controller etc.) interface plugged into the 5-Din 180' socket, transmitted tones of about 100mV RMS -> 10K, will mute the external mic. while the interface PTT is activated. When the microphone pressel is operated it will override any SSTV tones if present. The external interface Tx/AF input signal level is attenuated for the mic. input to approx 10mV RMS.
I used to be a Principal Test Engineer for Plessey UK, working on Military Communications, but I am now semi-retired and supporting the Radio Amateur. I get many requests for special interfaces and designs to enable use of both DATA and SSTV modes when the 'rig' does not seem to want to co-operate. Most recent was to CW KEY a TS-830 which uses MINUS 65V, via the Printer Port, and the user is now delighted with my custom solution.
Just email your requirements for a quotation ...... G8SLB@QSL.net
