Harold, I had the same problem interfacing my G4-450 to EchoMac. I found several old Apple Macintosh microphones in the junk box and remembered to try the one with the longer plug. The Mic has a pre-amp that Apple powers from the tip. The old Mic works great and I have had excellent audio reports. I don't know if your Mirror Door G4 has a Mic input so the Griffin iMic may be the best solution. When you launch EchoMac and you are validated, go to the EchoTest link first. It is a pretty cool site that echos everything back to you for setting microphone levels. I feel sure your iMac will be great but you need to play with it on line to before connecting to the nodes. Be sure you are using the latest version of EchoMac that is 1.1. It has a connect to box and ditched the old VOX that would get you in trouble. 73 de Dick, aa5vu EchoMac User on the AB5N-R link > Date: Tue, 15 Apr 2003 07:04:18 -0700 > From: Harold Polk <hpolk1 at mindspring.com> > Subject: [G4] Microphone for G4 Mirror Door > > I want to use an Amateur Radio program, EchoMac, but need to attach a > microphone to my G4 1ghz Mirror Door machine. Anyone have any recommendations > as to which mic will work and where it might be purchased? The information > with the G4 does not address the plug configuration or the impedance of the > connection. > I have one of the Griffin iMic attachments for the USB port but have not used > it so far. Any recommendations on using that attachment?? > Thanks > Harold