On both radiation monitors we use a 2.2k pull up resistor in our cables to get a 5-volt signal that goes low for each event.

The RM-BTD output is an open collector with a pulse width of 40 microseconds. When used with a 2.2k pull up resistor, we get a 5-volt signal that goes to 0.6 volts for 40 microseconds for each event.

The SRM-BTD has two output ports. The 3.5 mm output port, which we use has two output connectors. We use the tip of the 3.5 mm connector, which is connected to the ring of our stereo phone plug or input line on the BTD connector. The output signal is normally at a high level and goes low for about 150 microseconds for each event. The other signal that is available on the 3.5 mm connector is not used by us, it consists of 20 millisecond pulses that we planned to use if we ever did a SBI version of radiation. There is also an audio output on the SRM which we do not use. It is a 2.5 mm jack with an 8-volt AC coupled output suitable for amplifier input, tape recorder input, or RS232-compatible interface to personal computers. The signal may require attenuation in cables for some uses. We do not use it.