FREQUENCY COUNTER PLUG-IN 3 - 12.4 FREQUENCY CONVERTER FOR 5245 SERIES COUNTERS The 5255A Frequency Converter extends the range of the 5254L and 5256L counters from 3 to 12.4GHz and can also be used as a direct counting prescaler from 1 to 200MHz. The input voltage range is 100 mV to 0.7 V with an input impedance is 50 ohms with a type N (F) input connector.