diff --git a/Configuration.cpp b/Configuration.cpp
index 143701eb2..c95ce9a53 100644
--- a/Configuration.cpp
+++ b/Configuration.cpp
@@ -1416,7 +1416,10 @@ void Configuration::impl::set_rig_invariants ()
             }
         }
       ui_->CAT_serial_port_parameters_group_box->setEnabled (is_serial_CAT);
-      ui_->CAT_control_lines_group_box->setEnabled (is_serial_CAT && !is_hw_handshake);
+      ui_->CAT_control_lines_group_box->setEnabled (is_serial_CAT);
+      ui_->CAT_RTS_check_box->setEnabled (is_serial_CAT
+                                          && ui_->CAT_control_lines_group_box->isChecked ()
+                                          && !is_hw_handshake);
     }
 
   auto const& cat_port = ui_->CAT_port_combo_box->currentText ();
diff --git a/HamlibTransceiver.cpp b/HamlibTransceiver.cpp
index fcad237c2..ce2ee6ec6 100644
--- a/HamlibTransceiver.cpp
+++ b/HamlibTransceiver.cpp
@@ -261,7 +261,10 @@ HamlibTransceiver::HamlibTransceiver (int model_number, TransceiverFactory::Para
       if (params.force_line_control)
         {
           set_conf ("dtr_state", params.dtr_high ? "ON" : "OFF");
-          set_conf ("rts_state", params.rts_high ? "ON" : "OFF");
+          if (TransceiverFactory::handshake_hardware != params.handshake)
+            {
+              set_conf ("rts_state", params.rts_high ? "ON" : "OFF");
+            }
         }
     }