Once with Delphi wrote a host computer

based on the Spcomm control. Source:Unit unit1; interface uses  windows, Messages, sysutils, variants, Classes, Graphics, Controls, Forms,  dialogs, Stdctrls, Spcomm, Extctrls; type  tform1 = Class (TForm)      Comm1:TComm;    GroupBox1:TGroupBox;    go:TButton;     left:TButton;    right:TButton;    back:TButton;     left30:tbutton;    right30:tbutton;    yuan90: tbutton;    yuan360:tbutton;    groupbox2:tgroupbox;     Label5:TLabel;    Label6:TLabel;    Label7:TLabel;     Memo4:TMemo;    Memo5:TMemo;    Memo6:TMemo;     groupbox3:tgroupbox;    opencom:tbutton;    lianjie:Tbutton;    xinxi:tmemo;    procedure SendHex (s:string);     procedure Left30click (sender:tobject);     procedure OpencomClick (Sender:tobject) ;     procedure GoClick (Sender:tobject);     procedure BackClick (Sender: TObject);     procedure Commreceivedata (Sender:tobject; Buffer:pointer;  bufferlength:word);     procedure LeftClick (Sender:tobject);     procedure RightClick (Sender:tobject);     procedure W (sender:tobject; var Key:word; shift:tshiftstate);     procedure Formkeydown (Sender:tobject; var key:word;  shift: tshiftstate);     procedure formkeyup (Sender:tobject; var key:word;       shift:tshiftstate);   private    {Private Declarations}   Public    {Public declarations}  end; var  form1:tform1;  buf: string;  implementation {$R *.dfm}function Strtohex (Mstr:string;stlen:word):string;var     i:integer;begin    result:= ';     for I: = 1 to Stlen do     begin        if mstr[i]= #0 then             result:=result+ ' xx '          else         result:=result+inttohex (Ord (MStr[I ]), 2) + ";     end;end;  procedure Tform1.sendhex (s:string); VAR&NBSP;&NBSP;S2: STRING;&NBSP;&NBSP;BUF1:ARRAY[0..50000] of char;  i:integer;begin  s2:= ";   for i:= 1 to  length (s) do  begin    if ((Copy (s,i,1) >= ' 0 ') and (copy (s,i,1) <= ' 9 ')) Or ((Copy (s,i,1) >= ' a ') and (copy (s,i,1) <= ' F '))         or ((Copy (s,i,1) >= ' A ') and (copy (s,i,1) <= ' F ')) then    begin         s2:=s2+copy (s,i,1);     end;  end;  for i:=0 to (length (S2) div 2-1) do     buf1[i]:=char (Strtoint (' $ ' +copy (s2,i*2+1,2)));   comm1.writecommdata (Buf1, ( Length (S2) Div 2);  end; procedure Tform1.left30click (Sender:tobject); Begin  sendhex (' AA ');   //Send hex end;   procedure tform1.opencomclick (sender:tobject); begin   buf:= ' 0 ';    sendhex (BUF); if opencom. Caption = ' Open port ' then  begin  comm1.startcomm;   opencom. Caption: = ' off Port ';   endelse//if button1.caption = ' Close serial port ' then  begin  comm1.stopcomm;& Nbsp; opencom. Caption: = ' open port ';   end;end; procedUre Tform1.goclick (sender:tobject); begin  buf:= ' one ';   sendhex (BUF); end; procedure Tform1.backclick (sender:tobject); begin  buf:= ';   sendhex (BUF); end; procedure Tform1.leftclick (sender:tobject); begin  buf:= ';   sendhex (BUF); end; procedure Tform1.rightclick (sender:tobject); begin  buf:= ';   sendhex (BUF); end; procedure Tform1.commreceivedata (Sender:tobject; Buffer:pointer;  bufferlength:word); Var  strrecv:string;begin  setlength (strRecv , bufferlength);   move (Buffer^,pchar (STRRECV) ^,bufferlength);   xinxi. Lines.add (' Received: ' +inttostr (bufferlength) + ' bytes of data ');   xinxi. Lines.add (STRRECV);   xinxi. Invalidate, End;   procedure tform1.w (Sender:tobject; var Key:word; shift:tshiftstate); begin  buf:= ' one ';   sendhex (BUF); End; procedure TForm1.FormKeyDown ( Sender:tobject; var Key:word;  shift:tshiftstate); begin  if key=87 then     buf:= ' one ';       sendhex (BUF);   if key=83 then     buf:= ' 12 ';      sendhex (BUF);   if key=68 then     buf:= ' 13 ';      sendhex (BUF);   if key=65 then    buf:= ';  '     sendhex (BUF);    end;procedure tform1.formkeyup (Sender:tobject; var Key: word;  shift:tshiftstate); Begin    if key=87 then       sendhex (' ff ');     if key=65 then      sendhex (' ff ');    if key=68 then       sendhex (' ff ');    if Key= Then      sendhex (' ff '); end; end.

A host computer that was written by Delphi