MMDVM FM Relais
First check if your RX TX are ready for FM. Here i have ft7800 TX and FT857d as RX.
You must have a Piface card from JoyIt a USB Soundcard and Alsa utilitys are running. The WiringPi must be installed also the WiringPiDev librarys
One of the relais switch off the PTT from MMDVM to TX, digitalWrite (RELAIS1, HIGH) ;. The second switch off the sound from MMDVM to TX. digitalWrite (RELAIS2, HIGH)
digitalWrite (PTT, HIGH) set PTT from Mic input at the TX.
The audio path for FM is from RX out to USB Card Mic and from USB Card sound out to mic in from the TX unit. In this constelation it is possible to mix other sounds to the audio path as shown at the software. At the FT7800 this audio Path only works with Mic in PTT !!!!!!!!!!!!!!!!!!!!!!!! So there is no problem to switch back to digital sound from MMDVM
gcc -Wall relais.c -o relais -lwiringPi -lwiringPiDev
More details are following
schematics.jpg gives a overview how to connect raspi, mmdvm, piface and usb soundcard
at http://www.piface.org.uk/products/piface_digital/ you can find a description piface
relais without a extension is the binary
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.