Вот кусок примерный кода для пояснения вопроса:

unit Main;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, TrayIcon, Menus, ZAbstractConnection, ZConnection, StdCtrls,
 Buttons, ExtCtrls, IdBaseComponent, IdComponent, IdTCPConnection,
 IdTCPClient, IdTelnet, DB, ZAbstractRODataset, ZAbstractDataset, ZDataset, DateUtils;

type
 TMainForm = class(TForm)
   procedure FormCreate(Sender: TObject);
   procedure TimerTimer(Sender: TObject);
 private
   { Private declarations }
   IPList: TStringList;
   ThreadArray: array of TThread;
   PredScanTime: TDateTime;    
 public
   { Public declarations }
 end;

 TTelnetThread = class(TThread)
 private
   IdTelnet: TIdTelnet;
   PortNo: Integer;
   IP: String;
   LastPortText: String;
   procedure ParsePortText;
   procedure DataAvailable(Sender: TIdTelnet; const Buffer: String);
 protected
   procedure Execute; override;
 public
   constructor Create(IP: String);
 end;

var
 MainForm: TMainForm;

implementation

{$R *.dfm}

procedure TMainForm.FormCreate(Sender: TObject);
var
 i,j: Integer;
begin
 IPList := TStringList.Create;
 IPList.LoadFromFile(ExtractFileDir(Application.ExeName)+'\IP.txt');
 PLList := TStringList.Create;

 PredScanTime := Now;
 SetLength(ThreadArray, IPList.Count);
end;

constructor TTelnetThread.Create(IP: String);
begin
 inherited Create(True);
 IP := IP;
 LastPortText := '';
end;

procedure TTelnetThread.DataAvailable(Sender: TIdTelnet; const Buffer: String);
begin
 LastPortText := LastPortText + Buffer;
end;

procedure TTelnetThread.ParsePortText;
begin
  1) Парсим текст
  2) Вставляем в базу
end;

{Стартуем потоки каждые 5 минут}
procedure TMainForm.TimerTimer(Sender: TObject);
var
 i: Integer;
begin
 if DateTimeToUnix(Now) > DateTimeToUnix(PredScanTime) + 300 {ScanInterval} then begin
    PredScanTime := Now;

    for i := 0 to Length(ThreadArray) - 1 do begin
      ThreadArray[i] := TTelnetThread.Create(IPList[i],PLList[i]);
      ThreadArray[i].FreeOnTerminate := True;
      ThreadArray[i].Priority := tpLower;
      ThreadArray[i].Resume;
    end;
 end;
end;

procedure TTelnetThread.Execute;
var
 i: Integer;
begin
 try
   IdTelnet := TIdTelnet.Create(nil);
   IdTelnet.OnDataAvailable := DataAvailable;
   IdTelnet.Host := IP;
   IdTelnet.Connect(-1);

   Sleep(2000);
   IdTelnet.Write('admin'+#13#10);
   Sleep(2000);
   IdTelnet.Write('admin'+#13#10);
 except

 end;

 try
   for i := 1 to 64 do begin
     LastPortText := '';
     PortNo := i;
     IdTelnet.Write('get port '+IntToStr(i)+' data'+#13#10);
     sleep(1500);

     Synchronize(ParsePortText);
   end;
 except

 end;

 IdTelnet.Free;
end;

end;

end.

procedure TTelnetThread.DataAvailable(Sender: TIdTelnet; const Buffer: String);
begin
LastPortText := LastPortText + Buffer;
end;