I have an OPT 61c RLS 3.0 and have been having some problems with people not being heard when they place a call from the 61c to an internal or external number, but if they put the call on hold then retrieve it from hold it works fine they can be heard. This happened about 4 months ago and I replaced both PER SIG cards, and that worked, but now it's back. I am at a loss any help would be greatly appreciated.