I'm a victim of circumstance, Jeff.
I _must_ use the Engenius Durafon 4x system because of the wierd physical topology of a fireworks factory. No other product on the market (that we can afford) comes close to the features and range it offers.
But, like so many others, I'm having problems that Senao and EnGenius deny happens to anyone else but us.
EVERY handset we've bought (except the one run over by a truck...) has failed about four or five months out of warantee. The microphone fails. Squeezing or twisting the case lightly makes the problem come and go for a while, then it fails hard.
Obviously, it's a cracked run, broken feedthrough, or SMT component that breaks under normal handling and battery changing stresses to the case.
Unfortunately, without PCB maps or schematics, and with that damned 5- layer board, finding a broken run is a fruitless activity.
But they won't acknowlege the problem exists. Seems to me it would be easier to say, "We'll look into it" or some other pap designed to satisfy; but no. "You're the only person who's ever had that problem."
FWIW, there is no common factor of use that might explain it. Some phones are used outdoors, some in the factory buildings, and some in air conditioned desk service. All fail the same way, at about the same interval.
They'll all work for another month or two with an external headset, but that ultimately develops the same symptoms. Then it's rebuild or re-buy time.
The two we've recently sent in for repairs developed the same problem less than a month after they came back.