A method of operating a captioned telephone comprising the steps of dialing a telephone number to a relay gateway, connecting to the gateway over a communication network, performing a test to assess communication network quality, based on the test results, setting up the captioned telephone to operate in at least one of a first mode and a second mode wherein each of the first and second modes is one of (i) a PSTN mode in which data is communicated between the captioned telephone and the relay gateway via analog transmission and (ii) an IP mode in which data is communicated between the captioned telephone and the relay gateway via the Internet.