myMMX Tess Relay-Dienste is a communication app designed for the hearing-impaired to communicate with hearing individuals through telecommunication relay services provided by Tess. The app offers two main services: TeSign, a sign language interpretation service, and TeScript, a text interpretation service.

TeSign is a video call service where deaf individuals can connect with sign language interpreters. The interpreters then establish a phone call with the desired hearing conversation partner, facilitating communication in German Sign Language (DGS). The interpreters translate the conversation from DGS to spoken German and vice versa. TeSign also supports conversations involving simultaneous spoken language and sign language.

TeScript, on the other hand, is a text interpretation service. Deaf individuals can connect with text interpreters who facilitate phone calls with hearing conversation partners. The interpreters translate the conversation from written German to spoken German and vice versa.

Both services also support Voice Carry Over, allowing individuals with good spoken language skills to speak directly to the hearing conversation partner. The interpreter will then translate the responses into DGS or transmit them as text.

To use the app, users need to sign up for Tess Relay-Dienste or Telesign, ensure their mobile service provider allows VoIP (Voice over IP) usage, and have at least iOS 11 or a newer version installed.

To initiate a call, users simply need to enter their username and password, select the desired telecommunication relay service (TeSign or TeScript) from their address book, and establish a video or text connection with the interpreter. From there, the interpreter will initiate the call with the desired conversation partner and provide translation services between sign language or text and spoken language.