After 3 days of morning soldering, got the dtmf decoder with isolation transformer circuit working, The calls can be recorded to PC. I discovered a freeware voice recorder with silence detection called mega voice recorder available at http://www.globalsoftware.biz/
Now the remaining portions are
- Off hook Detector (I need parallel off hook with optical isolation)
- Ring Detector – for differentiating incoming and outgoing digits.
- PIC Micro for processing
- RS232 line driver
- EEProm storage
Once I start with PIC I think I’ll be back with a newversion of jaledit with JALV2.