1、控制POS机的客户显示屏

procedure  TFrmMain.ShowMoney(Money_Port:   String;Money_String:String);
//Moneey_Port：顾显接口Com1 or Com2    Money_String：顾显显示的内容
var
    PrnFileName:TextFile;
begin
    Assignfile(PrnFileName,Money_Port);
    printer.Canvas.Font.Name:='宋体';
    printer.Canvas.Font.Size:=8;
    printer.Canvas.Font.Charset:=GB2312_CHARSET;
    Rewrite(PrnFileName);
    write(PRNFileName,chr(12));         //清除顾显
    write(PRNFileName,chr(27)+chr(81)+chr(65)+Money_String+chR(13));       //显示信息
    CloseFile(PRNFileName);
end;

2、不换页走纸的打印

procedure TFrmMain.AddPrintStrings(Strings: TStrings);
var
  Prn: TextFile;
  i: word;
begin
  Assignfile(Prn,'lpt1');
    printer.Canvas.Font.Name:='宋体';
    printer.Canvas.Font.Size:=9;
    printer.Canvas.Font.Charset:=GB2312_CHARSET;
  try
    Rewrite(Prn);
    try
      for i := 0 to Strings.Count - 1 do
        writeln(Prn, Strings.Strings[i]);
    finally
      CloseFile(Prn);
    end;
  except
    on EInOutError do
      MessageBox(Handle,PChar('文本打印出错!'),'警告',MB_ICONEXCLAMATION or MB_OK);
  end;
end;

3、走纸换页的打印

procedure TFrmMain.PrintStrings(Strings: TStrings);
var
  Prn: TextFile;
  i: word;
begin
  AssignPrn(Prn);
  try
    Rewrite(Prn);
    printer.Canvas.Font.Name:='宋体';
    printer.Canvas.Font.Size:=9;
    printer.Canvas.Font.Charset:=GB2312_CHARSET;
    try
      for i := 0 to Strings.Count - 1 do
        writeln(Prn, Strings.Strings[i]);
    finally
      CloseFile(Prn);
    end;
  except
    on EInOutError do
      MessageBox(Handle,PChar('文本打印出错!'),'警告',MB_ICONEXCLAMATION or MB_OK);
  end;
end;

4、打开钱箱

procedure TFrmMain.OpenMoneyBox;
Var F:TextFile;
    PDStr:string;
begin
  //弹出钱箱功能
  PDStr:= Chr(27)+'p'+Chr(0)+Chr(60)+Chr(255);
  AssignFile(F, 'LPT1');
  Rewrite(F);
  Write(F, PDStr);
  CloseFile(F);
end;

总结：以上代码经过测试通过。