In radio transmission , a call that (a) includes at least the identification of the calling station and the called station, (b) is designed to establish communications with a particular station, and (c) usually includes a request to the called station to reply, although the request may be implied by the recitation of the call signs. [ From Weik '89 ] Note: A preliminary call may be made on a frequency dedicated to that purpose only, and the rest of the communications session take place on a different frequency or frequencies.
PRELIMINARY CALL
Meaning of PRELIMINARY CALL in English
Telecommunication standard terms English vocab. Английский словарь стандартных телекоммуникационных терминов. 2012