I have played with the loop length and recieve gain, at one location we lowered the recieve gain too low and the voicemail wasn't hearing DTMF tones and was not transferring calls, and that install was auto attendant answer.
Right now we aren't getting any complaints anymore since all are at current software versions and grounded properly, the customers who are aware of the sidetone know that NEC is working on it and if we have to put the B trunk cards in then we will. It's been a pain, but again, we like the DSX.
