How do I use TDD for the hearing impaired?

I know it's a stupid question, but I am new to the tty. Do I need service regular analog phone? I've always used in the past Sorenson VRS ATS. I have a new Superprint Ultratec 4425 TTY. Is this a good machine tty?

TDD / TTY is a relay service. The caller dials the ratings service, operator response and gives the caller the phone number destination. The operator will call the TTY remote and bidirectional communication is established between the audience and ATS operator. The relay operator through voice showing the terminal. You can also use ATS between the terminals and modem or fax modem to fax. Terminal 1 Terminal 2 marks and a link is made. With vs evil … I do not know, my experiance with ticker is Type 28, Type 33, Type 35 and Type 40 Model 43 …

Ultratec Superprint 4425 $395.00 Put the power of advanced technology at your fingertips with the deluxe Superprint 4425. This feature-packed TTY includes sophisticated capabilities, giving you more choices than ever It features direct connect with two built-in telephone jacks and advanced calling features like auto-busy redial, three way calling, and TTY transfer. Call progress tells you if the phone you are calling is ringing o…

Ultratec Superprint 4225 $400.99 Without direct connect features. FEATURES: Convenient GA/SK Keys. Easy-touch greeting memo. Tone or pulse dial. Keyboard dialing, follow-on dialing, call transfer. Memory dialing/redial. TTY Announcer. Baudot code (45.5/50 baud rate). Sticky Key feature (for single handed typing). Built-in, 34 character printer. 3 selectable print sizes. 32K memory. Date/time printed at the beginning of each call….

Ultratec Superprint 4425 $499.99 Put the power of advanced technology at your fingertips with the deluxe Superprint 4425. This feature-packed TTY includes sophisticated capabilities, giving you more choices than ever!…

Ultratec Superprint Pro80 Gold TTY …