INT 21 - WCED v1.6 - INSTALLATION CHECK
AX = 0A00h
DS:DX -> 6-byte buffer whose first two bytes must be 00h
Return: buffer offset 02h-05h filled with "Wced" if installed
Note:   WCED is a free command-line editor and history utility by Stuart
Russell

See also: 21FF

210A00 - WCED v1.6 - INSTALLATION CHECK