... (delay type) Center frequency 8.2±0.05MHz Scan frequency deviation ±500KHz Modulation frequency 150,160,170, ... 2 sets (or more) of testers being used on a same field, and their online connection is difficult, ... DS1, DS2 and DS3 not twinkling (lighting), it means that it is in best status. 3. Modulation frequency self ... 1&2 (factory setting), sound and light alarms will act at the same time and last for 2 ...