While I totally agree with Anij's solution for Anij only, there is still legal requirements that the USPS choose to ignore. Like Reba said, the USPS is a Federal agent and ADA is tricky here. In my 38 years of service I went out of my way to offer solutions and had them thrown back in my face each time with "That is an expense we don't want to cover" as each office has a budget and that office does not want the deaf to have a say in how the money is spent. I wont do it here but I could tell you stories about tty, vp, class in ASL for supervisiors, etc. that went nowhere. So my point is that to be legally covered a deaf person should first make it known that whichever company is expected to follow ADA and the Civil Rights Act of 1964 but if they resist then contact EEOC with proof that they resist.