JO 7110.65 5-2-16

Request a pilot to confirm assigned altitude on initial contact unless:

NOTE-

For the purpose of this paragraph, “initial contact” means a pilot's first radio contact with each sector/position.

The pilot states the assigned altitude, or

You assign a new altitude to a climbing or a descending aircraft, or

The Mode C readout is valid and indicates that the aircraft is established at the assigned altitude, or

TERMINAL. The aircraft was transferred to you from another sector/position within your facility (intrafacility). PHRASEOLOGY-

(In level flight situations),VERIFY AT (altitude/flight level).

(In climbing/descending situations),

(if aircraft has been assigned an altitude below the lowest useable flight level),VERIFY ASSIGNED ALTITUDE (altitude).

or

(If aircraft has been assigned a flight level at or above the lowest useable flight level),

VERIFY ASSIGNED FLIGHT LEVEL (flight level).

REFERENCE-

FAA Order JO 7110.65, Para 5-3-3 , Beacon/ADS-B Identification Methods.