Download of DMD 5620 1.4.1 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac app is an intellectual property of Seth Morabito. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
DMD 5620 is a terminal emulator that allows you to connect to a remote host using the Telnet protocol. To use advanced windowing features, the remote host must be able to speak the XT protocol (for example, AT&T UNIX System V Release 3, or Research UNIX Edition 8).
You may want to check out more Mac applications, such as DMDS App, DMD's Digital Performer 7 - Know It All! or Digital Media Doctor, which might be similar to DMD 5620.