Originally Posted by STS E
The answer is and the only answer, you need to use POTS lines.
Mystery solved and again i say it has nothing to do with the phone system or just because it is NEC. Your problem is what kind of phone lines are servicing the customer period. They are on IP/VOIP or what ever based on what you have communicated on
your post.

Actually not quite correct there, There is absolutely nothing wrong with Voip per se. The customer simply has to make an informed decision on compression as you wouldn't have these problems with other codecs that don't give as much compression.

Strange to see myself being quoted! :-)

Regards

R4 AKA OzzieGeorge