The Macintosh ED, also known as the Macintosh 512ke, is quite similar to the Macintosh 512k.
The Macintosh 512K enhanced (512Ke) was introduced in April 1986 as a cheaper alternative to the top-of-the-line Macintosh Plus, which had debuted three months previously.
It is the same as the Macintosh 512K but with the 800K disk drive and 128K of ROM used in the Macintosh Plus.
Like its predecessors, it has little room for expansion. Some companies did create memory upgrades that brought the machine up to 2 MB or more. It is the earliest Macintosh model able to run System Software 6.
It is also the earliest that can be used as an AppleShare server and, with a bridge Mac, communicate with modern devices