INT 61 u - PC/TCP kernel v2.05 - "net_connect" - ???
        AH = 13h
        BX = connection handle??? or FFFFh
        DX = protocol
            0000h ??? (returns error 0016h)
            0001h ???
            0002h ???
            0003h ???
            0004h ???
            0005h ???
        DS:SI -> result buffer???
Return: CF clear if successful
            AX = connection handle???
        CF set on error
            AX = error code (see INT 61"PC/TCP")
Note:   invokes AH=22h if BX=FFFFh on entry; also invokes AH=19h in various
          cases
SeeAlso: INT 61/AH=00h"PC/TCP",INT 61/AH=23h