通话频率 meaning in English

speech frequency
voice frequency

All ale personnel were on one frequency ( 1 - e )
所有机场执法人员都在统一通话频率上( 1 - e ) 。
Recordings are stored in first in first out basis , thus assuring perpetual recording without replacing cf card . the length of period recordings are stored within the microlog is dependent on the frequency of calls and cf cards storage size
不需更换任何录音组件，录音循环储存，依记忆卡容量及通话频率， ?录音在机内可保留数周至数月以上。