At 02:00 AM 10/24/08, you wrote: >Hi > >I'm looking for a circuit which removes dtmf tones and maybe other >tonebursts from the rx audio before it is fed to the tx. > >There are circuits around which use the MN3008 and MN3101 ics which >are both obsolete now so are no choice. One possibility would be to >replace them with similar ics from Coolaudio, but most likely these >would still be hard to get even though they're still made. > >Does anybody have a different approach for such a tone blocker? > >Thanks Martin
Use one of the off-the-shelf boards that are designed for that... they are made by Arcom and by ICS (who got the design from Scom) See <http://www.repeater-builder.com/arcom/arcom-rad-in-acc.html> and <http://www.ics-ctrl.com/dadm/dsdadm.html> The Arcom unit is available in a board with three units on it, see here: <http://www.arcomcontrollers.com/rc210/rad.html>
