procedure TESNHolterServiceClient.Check();
var
  RequestParameters: TJSONObject;
  ResponseDataType: byte;
  ResponseData: TBytes;
  Response: TJSONObject;
begin
Lock.Enter();
try
Connect();
try
RequestParameters:=TJSONObject.Create();
try
  RequestParameters.AddPair('Type', 'Check');
  //.
  Connection_WriteTypedData(Data_Type_JSON, TEncoding.UTF8.GetBytes(RequestParameters.ToString()));
  Connection_ReadTypedData(ResponseDataType, ResponseData);
  //.
  if (ResponseDataType <> Data_Type_JSON) then raise Exception.Create('response has incorrect data type'); //. =>
  //.
  Response:=(TJSONObject.ParseJSONValue(TEncoding.UTF8.GetString(ResponseData)) as TJSONObject);
  try
    Response_Check(Response);
  finally
    Response.Destroy();
  end;
finally
  RequestParameters.Destroy();
end;
finally
  Disconnect();
end;
finally
Lock.Leave();
end;
end;