[App_rpt-users] Can't Change CTCSS input threshold on RTCM menu

Unfortunately, on our CTCSS output, there is about 0.15 Volts when no signal, and 5 when there is signal. The RTCM thinks that there is Always a signal. I am trying to adjust this menu on the RTCM: 20 - Ext. CTCSS Input Threshold (850) (0-1023) When I hit 20, and then enter my new value, it is not updated, and stays at 850, this number is set and won't change. Any thoughts? If this doesen't work, we will probably try to use a diode or something to drop the voltage. Skyler K0WHB