Int 2F Fn 4800  - DOS 5+ Doskey - Installation Check                       [K]

   AX = 4800h

Return: AL = nonzero if installed (DOS 5.0 and 6.0 return AX=AA02h)
       ES = segment of DOSKEY resident portion

Note:  DOSKEY chains if AL is not 00h or 10h on entry

See Also: AX=4800h"PCED",AX=4810h