diff --git a/cubesatsim/cubesatsim.ino b/cubesatsim/cubesatsim.ino
index 33ba32d2..467adba0 100644
--- a/cubesatsim/cubesatsim.ino
+++ b/cubesatsim/cubesatsim.ino
@@ -3555,16 +3555,16 @@ void config_gpio() {
   pinMode(BPF_PIN, INPUT_PULLUP);  // Read LPF to see if present
 //  pinMode(SQUELCH, INPUT);	// Squelch from TXC
 
-//  if (digitalRead(BPF_PIN) == FALSE) {  
-  if (digitalRead(BPF_PIN) != FALSE) {  // force BPF present
+  if (digitalRead(BPF_PIN) == FALSE) {  
+//  if (digitalRead(BPF_PIN) != FALSE) {  // force BPF present
     Serial.println("BPF present - transmit enabled");
     filter_present = true;  
   }
   else
     Serial.println("BPF not present - no transmitting after CW ID");	 
 	
-  if (digitalRead(TXC_PIN) == FALSE) {	
-//  if (digitalRead(TXC_PIN) != FALSE) {   // force SR_FRS not present
+//  if (digitalRead(TXC_PIN) == FALSE) {	
+  if (digitalRead(TXC_PIN) != FALSE) {   // force SR_FRS not present
     Serial.println("SR_FRS present");
     sr_frs_present = true;
   }