diff --git a/TBF/Rig/TestMethods/iPerlCommunication/OpticalHeadTest.cs b/TBF/Rig/TestMethods/iPerlCommunication/OpticalHeadTest.cs
index 77c3809f5..a6f3cb489 100644
--- a/TBF/Rig/TestMethods/iPerlCommunication/OpticalHeadTest.cs
+++ b/TBF/Rig/TestMethods/iPerlCommunication/OpticalHeadTest.cs
@@ -55,7 +55,7 @@ namespace TBF.Rig.TestMethods.iPerlCommunication
                 string payload = "03";
                 RfidCommunicationService rfidCommunicationService = new RfidCommunicationService { ComPort = $"COM{iHead.RfidComPortNr}", WaitTimeAfterFailure = 2200, PassThroughWaitTime = 1500, MaxRetries = 3, TimeOut = 5000 };
                 rfidCommunicationService.RfidWrite(Params.u8_WakeUpInterval, payload);
-                return rfidCommunicationService.RfidRead(Params.u8_WakeUpInterval).ToString() == payload? "OK" : "Error";
+                return rfidCommunicationService.RfidRead<string>(Params.u8_WakeUpInterval).ToString() == payload ? "OK" : "Error";
             }
             catch (Exception ex)
             {
@@ -71,7 +71,7 @@ namespace TBF.Rig.TestMethods.iPerlCommunication
                 RfidCommunicationService rfidCommunicationService = new RfidCommunicationService { ComPort = $"COM{iHead.RfidComPortNr}", WaitTimeAfterFailure = 2200, PassThroughWaitTime = 1500, MaxRetries = 3, TimeOut = 5000 };
                 rfidCommunicationService.RfidWrite(SystemInfo.u8_system_state, payload);
                 Thread.Sleep(1000); // must be for pass thru params
-                return rfidCommunicationService.RfidRead(SystemInfo.u8_system_state).ToString() == payload ? "OK" : "Error";
+                return rfidCommunicationService.RfidRead<string>(SystemInfo.u8_system_state).ToString() == payload ? "OK" : "Error";
             }
             catch (Exception ex)
             {
@@ -89,7 +89,7 @@ namespace TBF.Rig.TestMethods.iPerlCommunication
                 {
                     RfidCommunicationService rfidCommunicationService = new RfidCommunicationService { ComPort = $"COM{iHead.RfidComPortNr}", WaitTimeAfterFailure = 2200, PassThroughWaitTime = 1500, MaxRetries = 3, TimeOut = 5000 };
                     //rfidCommunicationService.RfidWrite(Params.u8_Customer_Text, custText);
-                    return rfidCommunicationService.RfidRead(Params.u8_Customer_Text).ToString();
+                    return rfidCommunicationService.RfidRead<string>(Params.u8_Customer_Text).ToString();
                 }
             }
             catch (Exception ex)