Hello All, I am still working on this issue. What has been figured out is the microphone circuit appears to be the victim, in a round about way. If we cut off the microphone in any way the audible failure goes away. If we mute the phone it is linked to the failure goes away. The call box we use defaults to echo or loop back for audio testing so you can monitor audio quality. If we take the call box out of echo or loop and put it into handset mode (which has no loop back of audio) the failure also goes away.
So the question is does the call box in the system have to be set to loop back or echo mode during the test. I did not see the call box settings spelled out in any of the standards. In section 4.2.1 of 301 489-7 V1.2.1 it says: " A communication link shall be set up with a suitable base station simulator (hereafter called 'the test system')." That is all I have seen about the call box. Thank you for generously sharing your knowledge. Sincerely, Tony _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc